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  • richardmitnick 12:15 pm on November 2, 2021 Permalink | Reply
    Tags: "Rocky Exoplanets Are Even Stranger Than We Thought", , , , , , W.M. Keck Observatory (US)   

    From W.M. Keck Observatory (US) and NSF NOIRlab (US): “Rocky Exoplanets Are Even Stranger Than We Thought” 

    W.M. Keck Observatory two ten meter telescopes operated by California Institute of Technology(US) and The University of California(US), at Mauna Kea Observatory, Hawaii USA, altitude 4,207 m (13,802 ft). Credit: Caltech.

    Keck Laser Guide Star Adaptive Optics on two 10 meter Keck Observatory telescopes, Maunakea Hawaii USA, altitude 4,207 m (13,802 ft).

    Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).</a

    From W.M. Keck Observatory (US)

    November 2, 2021

    Mari-Ela Chock
    W.M. Keck Observatory
    mchock@keck.hawaii.edu
    Office (808) 881-3827
    Mobile (808) 554-0567

    Siyi Xu
    Associate Astronomer
    NSF’s NOIRLab
    Tel: +1 808-974-2538
    Email: siyi.xu@noirlab.edu

    Keith Putirka
    Professor, Department of Earth and Environmental Sciences
    California State University, Fresno
    Tel: +1 559-278-4524
    Email: kputirka@csufresno.edu

    Vanessa Thomas
    Public Information Officer
    NSF’s NOIRLab
    Tel: +1 520-318-8132
    Email: vanessa.thomas@noirlab.edu

    A New Astrogeology Study Suggests That Most Nearby Rocky Exoplanets Are Quite Unlike Anything in Our Solar System.

    1
    Rocky debris, the pieces of a former rocky planet that has broken up, spiral inward toward a white dwarf in this illustration. studying the atmospheres of white dwarfs that have been “polluted” by such debris, a Noirlab astronomer and a geologist have identified exotic rock types that do not exist in our solar system. The results suggest that nearby rocky exoplanets must be even stranger and more diverse than previously thought. Credit: J. da Silva/ NSF NOIRlab (US)/The Association of Universities for Research in Astronomy (AURA)(US).

    Astronomers have discovered thousands of planets orbiting stars in our galaxy – known as exoplanets. However, it’s difficult to know what exactly these planets are made of, or whether any resemble Earth. To try to find out, astronomer Siyi Xu of NSF’s NOIRLab partnered with geologist Keith Putirka of California State University-Fresno (US), to study the atmospheres of what are known as polluted white dwarfs.

    These are the dense, collapsed cores of once-normal stars like the Sun that contain foreign material from planets, asteroids, or other rocky bodies that once orbited the star but eventually fell into the white dwarf and “contaminated” its atmosphere. By looking for elements that wouldn’t naturally exist in a white dwarf’s atmosphere (anything other than hydrogen and helium), scientists can figure out what the rocky planetary objects that fell into the star were made of.

    Putirka and Xu looked at 23 polluted white dwarfs, all within about 650 light-years of the Sun, where calcium, silicon, magnesium, and iron had been measured with precision using W. M. Keck Observatory’s High-Resolution Echelle Spectrometer (HIRES) [below] on Maunakea in Hawai‘i, the Hubble Space Telescope, and other observatories. The scientists then used the measured abundances of those elements to reconstruct the minerals and rocks that would form from them.

    National Aeronautics and Space Administration(US)/European Space Agency [Agence spatiale européenne] [Europäische Weltraumorganisation](EU) Hubble Space Telescope

    “Combining the high sensitivity of Keck’s HIRES instrument and Hubble’s Cosmic Origins Spectrograph is the best way to measure the chemical compositions of extrasolar planetary materials accreted onto polluted white dwarfs,” said Xu.

    National Aeronautics Space Agency (US) Cosmic Origins Spectrograph.

    Putirka and Xu’s results are published in today’s issue of Nature Communications.

    They found that these white dwarfs have a much wider range of compositions than any of the inner planets in our solar system, suggesting their planets had a wider variety of rock types. In fact, some of the compositions are so unusual that Putirka and Xu had to create new names (such as “quartz pyroxenites” and “periclase dunites”) to classify the novel rock types that must have existed on those planets.

    “While some exoplanets that once orbited polluted white dwarfs appear similar to Earth, most have rock types that are exotic to our solar system,” said Xu. “They have no direct counterparts in the solar system.”

    Putirka describes what these new rock types might mean for the rocky worlds they belong to.

    “Some of the rock types that we see from the white dwarf data would dissolve more water than rocks on Earth and might impact how oceans are developed,” he explained. “Some rock types might melt at much lower temperatures and produce thicker crust than Earth rocks, and some rock types might be weaker, which might facilitate the development of plate tectonics.”

    Earlier studies of polluted white dwarfs had found elements from rocky bodies, including calcium, aluminum, and lithium. However, Putirka and Xu explain that those are minor elements (which typically make up a small part of an Earth rock) and measurements of major elements (which make up a large part of an Earth rock), especially silicon, are needed to truly know what kind of rock types would have existed on those planets.

    In addition, Putirka and Xu state that the high levels of magnesium and low levels of silicon measured in the white dwarfs’ atmospheres suggest that the rocky debris detected likely came from the interiors of the planets – from the mantle, not their crust.

    Some previous studies of polluted white dwarfs reported signs that continental crust existed on the rocky planets that once orbited those stars, but Putirka and Xu found no evidence of crustal rocks. However, the observations do not completely rule out that the planets had continental crust or other crust types.

    “We believe that if crustal rock exists, we are unable to see it, probably because it occurs in too small a fraction compared to the mass of other planetary components, like the core and mantle, to be measured,” Putirka stated.

    According to Xu, the pairing of an astronomer and a geologist was the key to unlocking the secrets hidden in the atmospheres of the polluted white dwarfs.

    “I met Keith Putirka at a conference and was excited that he could help me understand the systems that I was observing. He taught me geology and I taught him astronomy, and we figured out how to make sense of these mysterious exoplanetary systems.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    UCO Keck LRIS on Keck 1.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    Keck/MOSFIRE on Keck 1, Mauna Kea, Hawaii, USA.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.
    Keck OSIRIS on Keck 1

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    [ Keck/DEIMOS on Keck 2.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.

    NIRSPEC on Keck 2.

    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KECK Echellette Spectrograph and Imager (ESI)

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    Keck Cosmic Web Imager on Keck 2 schematic.

    Keck Cosmic Web Imager on Keck 2.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.

    Keck NIRC2 Camera on Keck 2
    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Keck Near-Infrared Echellette Spectrometer on Keck 2

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KCRM – Keck Cosmic Reionization Mapper KCRM on Keck 2.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

    KPF Keck Planet Finder on Keck 2

    NSF’s NOIRLab (National Optical-Infrared Astronomy Research Laboratory), the US center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the DOE’s SLAC National Accelerator Laboratory (US)). It is managed by The Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with The National Science Foundation (US) and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on Iolkam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O’odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.

     
  • richardmitnick 8:47 am on October 23, 2021 Permalink | Reply
    Tags: "Infant Planet Discovered by UH-Led Team Using Maunakea Telescopes", , , , , The planet 2m0437, W.M. Keck Observatory (US)   

    From W.M. Keck Observatory (US) : “Infant Planet Discovered by University of Hawai’i-Led Team Using Mauna Kea Telescopes” 

    W.M. Keck Observatory two ten meter telescopes operated by California Institute of Technology(US) and The University of California(US), at Mauna Kea Observatory, Hawaii USA, altitude 4,207 m (13,802 ft). Credit: Caltech.

    Keck Laser Guide Star Adaptive Optics on two 10 meter Keck Observatory telescopes, Maunakea Hawaii USA, altitude 4,207 m (13,802 ft).

    Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft).</a

    From W.M. Keck Observatory (US)

    October 22, 2021

    Mari-Ela Chock
    Tel 808-881-3827
    Cell 808-554-0567
    mchock@keck.hawaii.edu

    1
    A direct image of the planet 2m0437, which lies about 100 times the earth-sun distance from its parent star. the image was taken by ircs on the Subaru elescope on Mauna Kea. the much-brighter host star has been mostly removed, and the four “spikes” are artifacts produced by the optics of the telescope. Credit: Subaru telescope.

    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA,4,207 m (13,802 ft) above sea level

    One of the youngest planets ever found around a distant infant star has been discovered by an international team of scientists led by The University of Hawaiʻi-Mānoa(US) faculty, students, and alumni.

    Thousands of planets have been discovered around other stars, but what sets this one apart is that it is newly-formed and can be directly observed. The planet, named 2M0437b, joins a handful of objects advancing our understanding of how planets form and change with time, helping shed new light on the origin of the solar system and Earth.

    The in-depth research has been accepted for publication in the MNRAS.

    “This serendipitous discovery adds to an elite list of planets that we can directly observe with our telescopes,” explained lead author Eric Gaidos, a professor in the University of Hawaiʻi-Mānoa Department of Earth Sciences. “By analyzing the light from this planet we can say something about its composition, and perhaps where and how it formed in a long-vanished disk of gas and dust around its host star.”

    The researchers estimate that the planet is a few times more massive than Jupiter, and that it formed with its star several million years ago, around the time the main Hawaiian Islands first emerged above the ocean. The planet is so young that it is still hot from the energy released during its formation, with a temperature similar to the lava erupting from Kīlauea Volcano.

    Key Mauna Kea Telescopes

    In 2018, 2M0437b was first seen with the Subaru Telescope on Maunakea by Institute for Astronomy University of Hawai’i (US) (IfA) visiting researcher Teruyuki Hirano. For the past several years, it has been studied carefully utilizing other telescopes on the Mauna.

    Gaidos and his collaborators used W. M. Keck Observatory on Mauna Kea to monitor the position of the host star as it moved across the sky. With Keck Observatory’s Near-Infrared Camera, second generation (NIRC2) [below] in combination with the Keck II telescope’s adaptive optics system [above], the team was able to verify that planet 2M0437b was truly a companion to the star, and not a more distant object. The observations required three years because the star moves slowly across the sky.

    “The exquisite data from the Keck Observatory allowed us to confirm that the faint neighbor is moving through space along with its star, and thus is a true companion,” explained Dr. Adam Kraus, a professor in the Department of Astronomy at The University of Texas-Austin (US) and co-author on the paper. “Eventually, we might even be able to measure its orbital motion around the star.”

    The planet and its parent star lie in a stellar “nursery” called the Taurus Cloud. 2M0437b is on a much wider orbit than the planets in the solar system; its current separation is about 100 times the Earth-Sun distance, making it easier to observe. However, sophisticated adaptive optics are still needed to compensate for the image distortion caused by Earth’s atmosphere.

    “Two of the world’s largest telescopes, adaptive optics technology, and Mauna Kea’s clear skies were all needed to make this discovery,” said co-author Michael Liu, an astronomer at IfA. “We are all looking forward to more such discoveries, and more detailed studies of such planets with the technologies and telescopes of the future.”

    Future Research Potential

    Gathering more in-depth research about the newly-discovered planet may not be too far away. “Observations with space telescopes such as NASA’s Hubble and the soon-to-be-launched James Webb Space Telescope could identify gases in its atmosphere and reveal whether the planet has a moon-forming disk,” Gaidos added.

    National Aeronautics and Space Administration(US)/European Space Agency [Agence spatiale européenne] [Europäische Weltraumorganisation](EU) Hubble Space Telescope

    National Aeronautics Space Agency(USA)/European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU)/ Canadian Space Agency [Agence Spatiale Canadienne](CA) Webb Infrared Space Telescope(US) James Webb Space Telescope annotated. Scheduled for launch in October 2021 delayed to December 2021.

    The star that 2M0437b orbits is too faint to be seen with the unaided eye, but currently from Hawaiʻi, the young planet and other infant stars in the Taurus Cloud are almost directly overhead in the pre-dawn hours, north of the bright star Hokuʻula (Aldeberan) and east of the Makaliʻi (Pleiades) star cluster.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.[/caption]height=”375″ class=”size-full wp-image-32389″ /> Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    UCO Keck LRIS on Keck 1.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    Keck/MOSFIRE on Keck 1, Mauna Kea, Hawaii, USA.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.
    Keck OSIRIS on Keck 1

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    [ Keck/DEIMOS on Keck 2.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.

    NIRSPEC on Keck 2.

    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KECK Echellette Spectrograph and Imager (ESI)

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    Keck Cosmic Web Imager on Keck 2 schematic.

    Keck Cosmic Web Imager on Keck 2.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.

    Keck NIRC2 Camera on Keck 2
    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Keck Near-Infrared Echellette Spectrometer on Keck 2

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KCRM – Keck Cosmic Reionization Mapper KCRM on Keck 2.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

    KPF Keck Planet Finder on Keck 2

     
  • richardmitnick 10:56 am on October 13, 2021 Permalink | Reply
    Tags: "A Crystal Ball Into Our Solar System’s Future", , , , , W.M. Keck Observatory (US),   

    From W.M. Keck Observatory (US) : “A Crystal Ball Into Our Solar System’s Future” 

    From W.M. Keck Observatory (US)

    October 13, 2021

    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567
    mchock@keck.hawaii.edu

    Giant Gas Planet Orbiting a Dead Star Gives Glimpse Into the Predicted Aftermath of our Sun’s Demise.

    1
    Artist’s rendition of a newly-discovered jupiter-like exoplanet orbiting a white dwarf, or dead star. This system is evidence that planets can survive their host star’s explosive red giant phase and is the very first confirmed planetary system that serves as an analog to the fate of the sun and jupiter in our own solar system.
    Credit: Adam Makarenko/ W. M. Keck Observatory.

    Astronomers have discovered the very first confirmed planetary system that resembles the expected fate of our solar system, when the Sun reaches the end of its life in about five billion years.

    The researchers detected the system using W. M. Keck Observatory on Maunakea in Hawaiʻi; it consists of a Jupiter-like planet with a Jupiter-like orbit revolving around a white dwarf star located near the center of our Milky Way galaxy.

    “This evidence confirms that planets orbiting at a large enough distance can continue to exist after their star’s death,” says Joshua Blackman, an astronomy postdoctoral researcher at the The University of Tasmania (AU) and lead author of the study. “Given that this system is an analog to our own solar system, it suggests that Jupiter and Saturn might survive the Sun’s red giant phase, when it runs out of nuclear fuel and self-destructs.”

    The study is published in today’s issue of the journal Nature.

    “Earth’s future may not be so rosy because it is much closer to the Sun,” says co-author David Bennett, a senior research scientist at The University of Maryland (US) and The Goddard Space Flight Center | NASA (US). “If humankind wanted to move to a moon of Jupiter or Saturn before the Sun fried the Earth during its red supergiant phase, we’d still remain in orbit around the Sun, although we would not be able to rely on heat from the Sun as a white dwarf for very long.”

    A white dwarf is what main sequence stars like our Sun become when they die. In the last stages of the stellar life cycle, a star burns off all of the hydrogen in its core and balloons into a red giant star. It then collapses into itself, shrinking into a white dwarf, where all that’s left is a hot, dense core, typically Earth-sized and half as massive as the Sun. Because these compact stellar corpses are small and no longer have the nuclear fuel to radiate brightly, white dwarfs are very faint and difficult to detect.

    Animation showing an artist’s rendering of a main sequence star ballooning into a red giant as it burns the last of its hydrogen fuel, then collapses into a white dwarf. What remains is a hot, dense core roughly the size of Earth and about half the mass of the Sun. A gas giant similar to Jupiter orbits from a distance, surviving the explosive transformation. Credit: Adam Makarenko/W. M. Keck Observatory.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    height=”375″ class=”size-full wp-image-32389″ /> Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.[/caption]

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.


    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.


    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

     
  • richardmitnick 12:54 pm on September 14, 2021 Permalink | Reply
    Tags: "Xplore and W. M. Keck Observatory announce innovative collaboration", , W.M. Keck Observatory (US), Xplore Space Telescope (XST)   

    From W.M. Keck Observatory (US) : “Xplore and W. M. Keck Observatory announce innovative collaboration” 

    From W.M. Keck Observatory (US)

    September 14, 2021

    Keck to support science concept development of Xplore Space Telescope (XST)

    Xplore Inc., a commercial space company providing Space as a Service® today announced a collaboration with the W. M. Keck Observatory in Waimea, Hawai’i. The Keck Observatory, the world’s leading optical/infrared observatory, will assist Xplore in concept development and science case definition for the company’s family of Xplore Space Telescopes (XST).

    Xplore Space Telescope (XST)

    The XST series of commercial space telescopes take full advantage of Xplore’s high performance Xcraft® platform to carry a suite of innovative sensors to address a wide range of astronomical and planetary observations. The collaboration with the Keck Observatory will help align the observational capabilities of the XSTs with the needs of the astronomical community. By leveraging commercial practices and advanced technology, XSTs can be deployed in a fraction of the time and cost compared with existing space-based observatories, enabling more science for more astronomers.

    Dr. John O’Meara, Chief Scientist of the Keck Observatory, said, “One of the ways Keck stays at the forefront of astronomical discovery is through collaborations that advance new technologies and science capabilities. I am excited to support Xplore in defining the science opportunities for the world’s first series of commercial space science telescopes.”

    Lisa Rich, Founder and Chief Operating Officer said, “Our team is highly engaged in bringing new space-based capabilities that can be added to the portfolios of observations at leading observatories like Keck. Partnering with Keck Observatory allows Xplore to advance its mission to accelerate space science by adding value and access to the astronomical community.”

    The XST will drive a new paradigm for astronomical research by offering a fleet of highly cost-effective, space-based observatories that significantly expand availability of observations and data at an expedited pace. XSTs will operate in low Earth orbit (LEO) and beyond into the cislunar space region, providing a range of optical observations for a diverse set of customers. In the coming months, Xplore plans to announce its first telescope missions.

    Lisa Rich added, “Together with Keck, we are opening new avenues for science. Keck’s ground-based observatories today deliver the most scientifically advanced astronomy data on Earth. Xplore will deliver the ability to collect new scientific data from space-based telescopes in parallel – and we expect this mix of new capabilities will produce positive outcomes for the astronomical community.”

    An added benefit from the Xplore and Keck Observatory association will be the value of Xplore’s space telescopes to education. “I am particularly excited about Xplore’s openness to placing its space telescopes at the service of education,” remarked Ed Harris, Chief Development Officer of Keck Observatory. “Science will be the prime beneficiary of our collaboration, and we will also look to engage students and teachers across the country and throughout the world in STEM education opportunities afforded through this unique capability.”

    “The observatory’s mission is to advance the frontiers of astronomy, share our discoveries, and inspire the imagination of all,” Hilton Lewis, Director of Keck Observatory said, “Our association with Xplore is an innovative new way to advance these goals.”

    About Xplore Inc.

    Xplore is a commercial space company offering Space as a Service. Xplore provides hosted payloads, communication relay services and exclusive datasets to its customers via solutions provided by its Xcraft and LightCraft multi-mission platforms. Xplore’s mission is to expand robotic exploration via commercial missions at and beyond Earth, to the Moon, Mars, Venus, Lagrange points and near-Earth asteroids for commercial companies, national space agencies, national security agencies, sovereign space agencies and non-profit entities.
    Visit: https://www.xplore.com

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    height=”375″ class=”size-full wp-image-32389″ /> Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.[/caption]

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.


    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.


    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

     
  • richardmitnick 8:08 am on September 10, 2021 Permalink | Reply
    Tags: "A Black Hole Triggers a Premature Supernova", , , , In 2017 a particularly luminous and unusual source of radio waves was discovered in data taken by the Very Large Array (VLA) Sky Survey [VLASS]-a project that scans the night sky in radio wavelengths., Material from the core rapidly fell onto the stellar corpse and this led to the launching of a pair of jets at nearly the speed of light., , , Radio transient VT 1210+4956, The bright radio flare was caused by a black hole or neutron star crashing into its companion star in a never-before-seen process., W.M. Keck Observatory (US)   

    From W.M. Keck Observatory (US) : “A Black Hole Triggers a Premature Supernova” 

    From W.M. Keck Observatory (US)

    September 2, 2021 [Sorry, Keck, I do not know how I missed this.]

    The first observation of a brand-new kind of supernova had been predicted by theorists but never before confirmed.

    1
    This illustration shows a massive star that is about to explode. the explosion was triggered after its dead-star companion (a black hole or neutron star) plunged into the star’s core. scientists say that the black hole or neutron star rammed into the massive star, and then, as it traveled inward over the course of centuries, ejected a spiral of material from the star’s atmosphere (pictured surrounding the star). when it reached the star’s core, material from the core rapidly fell onto the stellar corpse and this led to the launching of a pair of jets at nearly the speed of light. in this artist’s depiction, the jets are shown tunneling through the star, and will soon set off the supernova explosion. after a few years, the supernova will crash through the bulk of the ejected spiral, which extends to about 10,000 times the size of the star. this will create the luminous transient radio source observed by the very large array.
    Credit: Chuck Carter.

    In 2017 a particularly luminous and unusual source of radio waves was discovered in data taken by the Very Large Array (VLA) Sky Survey [VLASS]-a project that scans the night sky in radio wavelengths.

    Now, led by The California Institute of Technology (US) graduate student Dillon Dong, a team of astronomers has established that the bright radio flare was caused by a black hole or neutron star crashing into its companion star in a never-before-seen process.

    “Massive stars usually explode as supernovae when they run out of nuclear fuel,” says Gregg Hallinan, professor of astronomy at Caltech. “But in this case, an invading black hole or neutron star has prematurely triggered its companion star to explode.” This is the first time a merger-triggered supernova has ever been confirmed.

    A paper about the findings, which includes data from W. M. Keck Observatory on Maunakea in Hawaiʻi, appears in the journal Science on September 3.

    Bright Flares in the Night Sky

    Hallinan and his team look for so-called radio transients—short-lived sources of radio waves that flare brightly and burn out quickly like a match lit in a dark room. Radio transients are an excellent way to identify unusual astronomical events, such as massive stars that explode and blast out energetic jets or the mergers of neutron stars.

    Using Keck Observatory’s Low Resolution Imaging Spectrometer (LRIS) [below], the team then made follow-up optical observations of the radio source’s home galaxy and discovered a massive outflow of material ejected from a central location, suggesting there was an energetic explosion of a massive star.

    As Dong sifted through the VLA’s massive dataset, he singled out an extremely luminous source of radio waves from the VLA survey called VT 1210+4956. This source is tied for the brightest radio transient ever associated with a supernova.

    Dong determined that the bright radio energy was originally a star surrounded by a thick and dense shell of gas. This gas shell had been cast off the star a few hundred years before the present day. VT 1210+4956, the radio transient, occurred when the star finally exploded in a supernova and the material ejected from the explosion interacted with the gas shell. Yet, the gas shell itself, and the timescale on which it was cast off from the star, were unusual, so Dong suspected that there might be more to the story of this explosion.

    Two Unusual Events

    Following Dong’s discovery, Caltech graduate student Anna Ho (PhD ’20) suggested that this radio transient be compared with a different catalog of brief bright events in the X-ray spectrum. Some of these X-ray events were so short-lived that they were only present in the sky for a few seconds of Earth time. By examining this other catalog, Dong discovered a source of X-rays that originated from the same spot in the sky as VT 1210+4956. Through careful analysis, Dong established that the X-rays and the radio waves were likely coming from the same event.

    “The X-ray transient was an unusual event—it signaled that a relativistic jet was launched at the time of the explosion,” says Dong. “And the luminous radio glow indicated that the material from that explosion later crashed into a massive torus of dense gas that had been ejected from the star centuries earlier. These two events have never been associated with each other, and on their own they’re very rare.”

    A Mystery Solved

    So, what happened? After careful modeling, the team determined the most likely explanation—an event that involved some of the same cosmic players that are known to generate gravitational waves.

    They speculated that a leftover compact remnant of a star that had previously exploded—that is, a black hole or a neutron star—had been closely orbiting around a star. Over time, the black hole had begun siphoning away the atmosphere of its companion star and ejecting it into space, forming the torus of gas. This process dragged the two objects ever closer until the black hole plunged into the star, causing the star to collapse and explode as a supernova.

    The X-rays were produced by a jet launched from the core of the star at the moment of its collapse. The radio waves, by contrast, were produced years later as the exploding star reached the torus of gas that had been ejected by the inspiraling compact object.

    Astronomers know that a massive star and a companion compact object can form what is called a stable orbit, in which the two bodies gradually spiral closer and closer over an extremely long period of time. This process forms a binary system that is stable for millions to billions of years but that will eventually collide and emit the kind of gravitational waves that were discovered by LIGO in 2015 and 2017.

    However, in the case of VT 1210+4956, the two objects instead collided immediately and catastrophically, producing the blasts of X-rays and radio waves observed. Although collisions such as this have been predicted theoretically, VT 1210+4956 provides the first concrete evidence that it happens.

    Serendipitous Surveying

    The VLA Sky Survey produces enormous amounts of data about radio signals from the night sky, but sifting through that data to discover a bright and interesting event such as VT 1210+4956 is like finding a needle in a haystack. Finding this particular needle, Dong says, was, in a way, serendipitous.

    “We had ideas of what we might find in the VLA survey, but we were open to the possibility of finding things we didn’t expect,” explains Dong. “We created the conditions to discover something interesting by conducting loosely constrained, open-minded searches of large data sets and then taking into account all of the contextual clues we could assemble about the objects that we found. During this process you find yourself pulled in different directions by different explanations, and you simply let nature tell you what’s out there.”
    ______________________________________________________________________________________________________________
    ABOUT LRIS [below]

    The Low Resolution Imaging Spectrometer (LRIS) is a very versatile and ultra-sensitive visible-wavelength imager and spectrograph built at the California Institute of Technology by a team led by Prof. Bev Oke and Prof. Judy Cohen and commissioned in 1993. Since then it has seen two major upgrades to further enhance its capabilities: the addition of a second, blue arm optimized for shorter wavelengths of light and the installation of detectors that are much more sensitive at the longest (red) wavelengths. Each arm is optimized for the wavelengths it covers. This large range of wavelength coverage, combined with the instrument’s high sensitivity, allows the study of everything from comets (which have interesting features in the ultraviolet part of the spectrum), to the blue light from star formation, to the red light of very distant objects. LRIS also records the spectra of up to 50 objects simultaneously, especially useful for studies of clusters of galaxies in the most distant reaches, and earliest times, of the universe. LRIS was used in observing distant supernovae by astronomers who received the Nobel Prize in Physics in 2011 for research determining that the universe was speeding up in its expansion.

    See the full article here.
    See also the NRAO article here.
    See also the Caltech article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    height=”375″ class=”size-full wp-image-32389″ /> Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.[/caption]

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.


    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.


    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

     
  • richardmitnick 12:30 pm on August 4, 2021 Permalink | Reply
    Tags: "Observatories Assemble: NASA’s Juno Spacecraft Joins W. M. Keck Observatory and Japan’s Hisaki Satellite to Solve 'Energy Crisis' on Jupiter", , , , , , W.M. Keck Observatory (US)   

    From W.M. Keck Observatory (US) : “Observatories Assemble: NASA’s Juno Spacecraft Joins W. M. Keck Observatory and Japan’s Hisaki Satellite to Solve ‘Energy Crisis’ on Jupiter” 

    From W.M. Keck Observatory (US)

    August 4, 2021
    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567
    mchock@keck.hawaii.edu

    1
    Jupiter is shown in visible light for context underneath an artistic impression of the jovian upper atmosphere’s infrared glow. the brightness of this upper atmosphere layer corresponds to temperatures, from hot to cold, in this order: white, yellow, bright red and lastly, dark red. the aurorae are the hottest regions and the image shows how heat may be carried by winds away from the aurora and cause planet-wide heating.
    Credits: J. O’Donoghue (Japan Aerospace Exploration Agency [ (国立研究開発法人宇宙航空研究開発機構](JP) )/A. Simon/J. Schmidt Hubble/National Aeronautics Space Agency (US)/European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU).

    Sitting more than five times the distance from the Sun as Earth, Jupiter is not expected to be particularly warm. Based on the amount of sunlight received, the average temperature in the planet’s upper atmosphere should be about minus 100 degrees Fahrenheit or a chilly minus 73 Celsius. Instead, the measured value soars to around 800 degrees Fahrenheit or 426 Celsius. The source of this extra heat has remained elusive for 50 years, causing scientists to refer to the discrepancy as an “energy crisis” for the planet.

    Recently, an international team assembled observations from a trio of observatories — NASA’s Juno spacecraft, W. M. Keck Observatory on Mauna Kea in Hawaiʻi [above], and the Hisaki satellite from the Japan Aerospace Exploration Agency (JAXA) — to discover the likely source of Jupiter’s thermal boost.

    2
    JAXA Hisaki satellite.

    “We found that Jupiter’s intense aurora, the most powerful in the solar system, is responsible for heating the entire planet’s upper atmosphere to surprisingly high temperatures,” said James O’Donoghue of the JAXA Institute of Space and Astronautical Science, Sagamihara, Japan. O’Donoghue began the research while at NASA’s Goddard Space Flight Center in Greenbelt, Maryland and is lead author of a paper about this research published today (August 4) in the journal Nature.

    Auroras occur when electrically charged particles are caught in a planet’s magnetic field. These spiral along invisible lines of force in the magnetic field towards the planet’s magnetic poles, striking atoms and molecules in the atmosphere to release light and energy. On Earth, this leads to the colorful light show that forms the aurora Borealis and Australis, also known as the northern and southern lights. At Jupiter, material erupting from its volcanic moon, Io, leads to the most powerful aurora in the solar system and enormous heating in the upper atmosphere over the polar regions of the planet.

    The idea that the aurora could be the source of Jupiter’s mysterious energy had been proposed previously but observations have been unable to confirm or deny this, until now.

    Global models of Jupiter’s upper atmosphere suggested that winds heated by the aurora and headed to the equator would be overwhelmed and redirected by westward winds driven by the planet’s rapid rotation. This would prevent the auroral energy from escaping the polar regions and heating the whole atmosphere. However, this new observational result suggests that such trapping is not occurring, and that the westward winds may be relatively weaker than expected compared with equatorward winds.

    High-resolution temperature maps from Keck Observatory, combined with magnetic field data from Hisaki and Juno, allowed the team to catch the aurora in the act of sending what appears to be a pulse of heat toward Jupiter’s equator.

    Jupiter is first shown in visible light for context before an artistic impression of the Jovian upper atmosphere’s infrared glow is overlain. The brightness of this upper atmosphere layer corresponds to temperatures, from hot to cold, in this order: white, yellow, bright red and lastly, dark red. The aurorae are the hottest regions and the animation shows how heat may be carried by winds away from the aurora and cause planet-wide heating. At the end, real data is added with a temperature scale, indicating the observed global temperatures measured in the study. Credit: J. O’Donoghue (JAXA)/Hubble/NASA/ESA/A. Simon/J. Schmidt.
    ______________________________________________________________________________________________________________
    The team observed Jupiter with the Keck II telescope for five hours on two separate nights in April 2016 and January 2017. Using the Near-Infrared Spectrograph (NIRSPEC) on Keck II, heat from electrically charged hydrogen molecules (H3+ ions) in Jupiter’s atmosphere was traced from the planet’s poles down to the equator.

    Previous maps of the upper atmospheric temperature were formed using images consisting of only several pixels. That’s not enough resolution to see how the temperature might be changing across the planet, providing few clues as to the origin of the extra heat.

    To improve the situation, the team utilized the power of Keck II to take many more temperature measurements across the face of the planet and only included measurements with uncertainty in the recorded value of less than five percent. This took years of careful work and yielded temperature maps with over 10,000 individual data points, the highest resolution to date.

    “We’ve attempted this multiple times with other instruments but with Keck’s NIRSPEC, we were able to measure for the very first time the light from Jupiter all the way to the equator quickly enough that we can then map out the temperature and ionospheric density,” said Tom Stallard, a co-author of the paper at the University of Leicester, Leicester, United Kingdom.

    Instead of high temperatures only in the polar regions near the aurora, which would be expected if the heat was trapped there, these detailed maps showed that the heat in the upper atmosphere was more widely distributed, with a gradual decrease in temperature closer to the equator.

    “We also revealed a strange localized region of heating well away from the aurora – a long bar of heating unlike anything we’ve seen before,” said Stallard. “Though we can’t be sure what this feature is, I am convinced it’s a rolling wave of heat flowing equatorward from the aurora.”

    Additionally, observations from JAXA’s Hisaki satellite showed that conditions at the time of the Keck II temperature observations could generate a strong aurora on Jupiter. From orbit around Earth, Hisaki has observed the aurora-generating magnetic field around Jupiter since the mission’s launch in 2013. This long-term monitoring has revealed that Jupiter’s magnetic field is strongly influenced by the solar wind; a stream of high-energy particles that emanates from the Sun. The solar wind carries its own magnetic field and when this meets Jupiter’s planetary field, the latter is compressed. At the time of the Keck II observations, Hisaki showed that pressure from the solar wind was particularly high at Jupiter and the field compression is likely to have created an enhanced aurora.

    Finally, observations from Juno in orbit around Jupiter provided the precise location of the aurora on the planet.

    “Juno’s magnetic field data provided us with a ‘ground truth’ as to where the aurora was. This information isn’t readily available from heat maps, as heat leaks away in many directions,” said O’Donoghue. “Picture this like a beach: if the hot atmosphere is water, the magnetic field mapped by Juno is the shoreline, and the aurora is the ocean, we found that water left the ocean and flooded the land, and Juno revealed where that shoreline was to help us understand the degree of flooding.”

    “It was pure luck that we captured this potential heat-shedding event,” adds O’Donoghue. “If we’d observed Jupiter on a different night, when the solar wind pressure had not recently been high, we would have missed it!”

    The team will continue to analyze the data and produce more maps; their goal is to catch Jupiter’s aurora spew another hot spot, this time observing it over a 2-3 day period so they can track its energy as it moves around the planet.

    “Can we observe one of these features moving? Will it show the flow of auroral heat in action? How does this flow of energy then affect the surrounding magnetic fields that we now know are so complex? It’s a thrilling set of research questions in a region of Jupiter’s ionosphere that, five years ago, we thought of as mundane,” said Stallard.
    ______________________________________________________________________________________________________________

    ABOUT NIRSPEC

    The Near-Infrared Spectrograph (NIRSPEC) is a unique, cross-dispersed echelle spectrograph that captures spectra of objects over a large range of infrared wavelengths at high spectral resolution. Built at the UCLA Infrared Laboratory by a team led by Prof. Ian McLean, the instrument is used for radial velocity studies of cool stars, abundance measurements of stars and their environs, planetary science, and many other scientific programs. A second mode provides low spectral resolution but high sensitivity and is popular for studies of distant galaxies and very cool low-mass stars. NIRSPEC can also be used with Keck II’s adaptive optics (AO)system to combine the powers of the high spatial resolution of AO with the high spectral resolution of NIRSPEC. Support for this project was provided by the Heising-Simons Foundation (US).

    See the full article here.
    See the article also from NASA Goddard here.


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    height=”375″ class=”size-full wp-image-32389″ /> Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.[/caption]

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.


    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.


    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

     
  • richardmitnick 12:53 pm on July 31, 2021 Permalink | Reply
    Tags: , 2mass j22081363+2921215-a nearby brown dwarf, , , , , W.M. Keck Observatory (US)   

    From W.M. Keck Observatory (US) : “Astronomers Probe Layer-Cake Structure of Brown Dwarf’s Atmosphere” 

    From W.M. Keck Observatory (US)

    July 30, 2021

    1
    Artist’s concept of 2mass j22081363+2921215-a nearby brown dwarf. though only roughly 115 light-years away, the brown dwarf is too distant for any atmospheric features to be photographed. instead, researchers used w. m. keck observatory’s mosfire instrument to study the colors and brightness variations of the brown dwarf’s layer-cake cloud structure, as seen in near-infrared light. mosfire also collected the spectral fingerprints of various chemical elements contained in the clouds and how they change over time.
    Credit: Leah Hustak (STScI), Greg T. Bacon (STScI) National Aeronautics Space Agency (US),European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU), Space Telescope Science Institute (US).

    Jupiter may be the bully planet of our solar system because it’s the most massive planet, but it’s actually a runt compared to many of the giant planets found around other stars.

    These alien worlds, called super-Jupiters, weigh up to 13 times Jupiter’s mass. Astronomers have analyzed the composition of some of these monsters, but it has been difficult to study their atmospheres in detail because these gas giants get lost in the glare of their parent stars.

    Researchers, however, have a substitute: the atmospheres of brown dwarfs, so-called failed stars that are up to 80 times Jupiter’s mass. These hefty objects form out of a collapsing cloud of gas, as stars do, but lack the mass to become hot enough to sustain nuclear fusion in their cores, which powers stars.

    Instead, brown dwarfs share a kinship with super-Jupiters. Both types of objects have similar temperatures and are extremely massive. They also have complex, varied atmospheres. The only difference, astronomers think, is their pedigree. Super-Jupiters form around stars; brown dwarfs often form in isolation.

    A team of astronomers, led by Elena Manjavacas of the Space Telescope Science Institute in Baltimore, Maryland, has tested a new way to peer through the cloud layers of these nomadic objects. The researchers used an instrument at W. M. Keck Observatory on Mauna Kea in Hawaiʻi to study in near-infrared light the colors and brightness variations of the layer-cake cloud structure in the nearby, free-floating brown dwarf known as 2MASS J22081363+2921215.

    The Keck Observatory instrument, called the Multi-Object Spectrograph for Infrared Exploration (MOSFIRE) [below], also analyzed the spectral fingerprints of various chemical elements contained in the clouds and how they change with time. This is the first time astronomers have used MOSFIRE in this type of study.

    These measurements offered Manjavacas a holistic view of the brown dwarf’s atmospheric clouds, providing more detail than previous observations of this object. Pioneered by Hubble observations, this technique is difficult for ground-based telescopes to do because of contamination from Earth’s atmosphere, which absorbs certain infrared wavelengths. This absorption rate changes due to the weather.

    3
    This graphic shows successive layers of clouds in the atmosphere of a nearby, free-floating brown dwarf. Breaks in the upper cloud layers allowed astronomers to probe deeper into the atmosphere of the brown dwarf called 2MASS J22081363+2921215. Brown dwarfs are more massive than planets but too small to sustain nuclear fusion, which powers stars. This illustration is based on infrared observations of the clouds’ colors and brightness variations, as well as the spectral fingerprints of various chemical elements contained in the clouds and atmospheric modeling. Credit: Andi James (STScI)NASA, ESA, STScI.

    “The only way to do this from the ground is by using Keck’s high-resolution MOSFIRE instrument because it allows us to observe multiple stars simultaneously with our brown dwarf,” said Manjavacas, a former staff astronomer at Keck Observatory and the lead author of the study. “This allows us to correct for the contamination introduced by the Earth’s atmosphere and measure the true signal from the brown dwarf with good precision. So, these observations are a proof-of-concept that MOSFIRE can do these types of studies of brown dwarf atmospheres.”

    She decided to study this particular brown dwarf because it is very young and therefore extremely bright. It has not cooled off yet. Its mass and temperature are similar to those of the nearby giant exoplanet Beta Pictoris b, discovered in 2008 near-infrared images taken by the European Southern Observatory’s Very Large Telescope in northern Chile.

    “We don’t have the ability yet with current technology to analyze in detail the atmosphere of Beta Pictoris b,” Manjavacas said. “So, we’re using our study of this brown dwarf’s atmosphere as a proxy to get an idea of what the exoplanet’s clouds might look like at different heights of its atmosphere.”

    Both the brown dwarf and Beta Pictoris b are young, so they radiate heat strongly in the near-infrared. They are both members of a flock of stars and sub-stellar objects called the Beta Pictoris moving group, which shares the same origin and a common motion through space. The group, which is about 33 million years old, is the closest grouping of young stars to Earth. It is located roughly 115 light-years away.

    While they’re cooler than bona fide stars, brown dwarfs are still extremely hot. The brown dwarf in Manjavacas’ study is a sizzling 2,780 degrees Fahrenheit (1,527 degrees Celsius).

    The giant object is about 12 times heavier than Jupiter. As a young body, it is spinning incredibly fast, completing a rotation every 3.5 hours, compared to Jupiter’s 10-hour rotation period. So, clouds are whipping around the planet, creating a dynamic, turbulent atmosphere.

    Keck Observatory’s MOSFIRE instrument stared at the brown dwarf for 2.5 hours, watching how the light filtering up through the atmosphere from the dwarf’s hot interior brightens and dims over time. Bright spots that appeared on the rotating object indicate regions where researchers can see deeper into the atmosphere, where it is hotter. Infrared wavelengths allow astronomers to peer deeper into the atmosphere. The observations suggest the brown dwarf has a mottled atmosphere with scattered clouds. If viewed close-up, the planet might resemble a carved Halloween pumpkin, with light escaping from the hot interior.

    Its spectrum reveals clouds of hot sand grains and other exotic elements. Potassium iodide traces the object’s upper atmosphere, which also includes magnesium silicate clouds. Moving down in the atmosphere is a layer of sodium iodide and magnesium silicate clouds. The final layer consists of aluminum oxide clouds. The atmosphere’s total depth is 446 miles (718 kilometers). The elements detected represent a typical part of the composition of brown dwarf atmospheres, Manjavacas said.

    She and her team used computer models of brown dwarf atmospheres to determine the location of the chemical compounds in each cloud layer.

    The study will be published in The Astronomical Journal.

    Manjavacas’ plan is to use Keck Observatory’s MOSFIRE to study other atmospheres of brown dwarfs and compare them to those of gas giants. Future telescopes such as NASA’s James Webb Space Telescope, an infrared observatory scheduled to launch later this year, will provide even more information about a brown dwarf’s atmosphere.

    “JWST will give us the structure of the entire atmosphere, providing more coverage than any other telescope,” Manjavacas said.

    She hopes that MOSFIRE can be used in tandem with JWST to sample a wide range of brown dwarfs and gain a better understanding of brown dwarfs and giant planets.

    “Exoplanets are so much more diverse than what we see locally in the solar system,” said Keck Observatory Chief Scientist John O’Meara. “It’s work like this, and future work with Keck and JWST, that will give us a fuller picture of the diversity of planets orbiting other stars.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    height=”375″ class=”size-full wp-image-32389″ /> Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.[/caption]

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.


    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.


    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

     
  • richardmitnick 10:58 am on July 29, 2021 Permalink | Reply
    Tags: "HR 8799 Super-Jupiters’ Days Measured for the First Time Gives a New Spin on Unraveling Planet Formation Mystery", , , , , W.M. Keck Observatory (US)   

    From W.M. Keck Observatory (US) : “HR 8799 Super-Jupiters’ Days Measured for the First Time Gives a New Spin on Unraveling Planet Formation Mystery” 

    From W.M. Keck Observatory (US)

    July 29, 2021

    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567

    W. M. Keck Observatory Planet Imager and Characterizer Instrument Delivers First Science, Capturing Spin Measurements of HR 8799 Exoplanets.

    1
    Artist’s rendition of hr 8799 planets b, c, d, and e as viewed in the infrared.
    Credit: Adam Makarenko/W. M. Keck Observatory.

    Astronomers have captured the first-ever spin measurements of HR 8799, the famed system that made history as the very first exoplanetary system to have its image taken.

    Discovered in 2008 by two Maunakea Observatories in Hawaiʻi – W. M. Keck Observatory and the international Gemini Observatory, a Program of NSF’s NOIRLab – the HR 8799 star system is located 129 light-years away and has four planets more massive than Jupiter, or super-Jupiters: HR 8799 planets b, c, d, and e.

    None of their rotation periods had ever been measured, until now.

    The breakthrough was made possible by a California Institute of Technology (US) and Keck Observatory-led science and engineering team that has developed an instrument capable of observing known imaged exoplanets at spectral resolutions that are detailed enough to allow astronomers to decipher how fast the planets are spinning.

    Using the state-of-the-art Keck Planet Imager and Characterizer (KPIC) on the Keck II telescope atop Hawaiʻi Island’s Maunakea, astronomers found that the minimum rotation speeds of HR 8799 planets d and e clocked in at 10.1 km/s and 15 km/s, respectively. This translates to a length of day that could be as short as three hours or could be up to 24 hours such as on Earth depending on the axial tilts of the HR 8799 planets, which are currently undetermined. For context, one day on Jupiter lasts nearly 10 hours; its rotation speed is about 12.7 km/s.

    As for the other two planets, the team was able to constrain the spin of HR 8799 c to an upper limit of less than 14 km/s; planet b’s rotation measurement was inconclusive.

    The findings are KPIC’s first science results, which have been accepted for publication in The Astronomical Journal.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    UCO Keck LRIS on Keck 1.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.

    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    [caption id="attachment_70877" align="alignnone" width="200"] Keck Cosmic Web Imager on Keck 2 schematic.


    Keck Cosmic Web Imager on Keck 2.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.


    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

     
  • richardmitnick 11:21 am on July 12, 2021 Permalink | Reply
    Tags: "Teardrop Star Reveals Hidden Supernova Doom", Astronomers have made the rare sighting of two stars spiraling to their doom by spotting the tell-tale signs of a teardrop-shaped star., , , Chandrasekhar mass limit, , , The couple – a binary star system called HD265435, Type Ia supernovae are important for cosmology as ‘standard candles.’, W.M. Keck Observatory (US)   

    From W.M. Keck Observatory (US) : “Teardrop Star Reveals Hidden Supernova Doom” 

    From W.M. Keck Observatory (US)

    July 12, 2021

    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567

    1
    Artist’s impression of the hd265435 system at around 30 million years from now, with the smaller white dwarf distorting the hot subdwarf into a distinct ‘teardrop’ shape. Credit: Mark Garlick/University of Warwick (UK).

    Astronomers have made the rare sighting of two stars spiraling to their doom by spotting the tell-tale signs of a teardrop-shaped star.

    The tragic shape is caused by a massive nearby white dwarf distorting the star with its intense gravity, which will also be the catalyst for an eventual supernova that will consume both. Found by an international team of astronomers and astrophysicists led by the University of Warwick (UK), it is one of only a very small number of star systems discovered that will one day see a white dwarf star reignite its core.

    The team’s new research is published in today’s issue (July 12) of the journal Nature Astronomy.

    With the help of W. M. Keck Observatory on Maunakea in Hawaiʻi, the astronomers were able to confirm that the two stars are in the early stages of a spiral that will likely end in a Type Ia supernova – a type that helps astronomers determine how fast the universe is expanding.

    The couple – a binary star system called HD265435 – is located roughly 1,500 light-years away; it is comprised of a hot subdwarf star and a white dwarf star orbiting each other closely at a dizzying rate of around 100 minutes. White dwarfs are ‘dead’ stars that have burned all their fuel and collapsed in on themselves, making them small but extremely dense.

    A type Ia supernova is generally thought to occur when a white dwarf star’s core reignites, leading to a thermonuclear explosion. There are two scenarios where this can happen. In the first, the white dwarf gains enough mass to reach 1.4 times the mass of our Sun, known as the Chandrasekhar limit. HD265435 fits in the second scenario, in which the total mass of a close stellar system of multiple stars is near or above this limit. Only a handful of other star systems have been discovered that will reach this threshold and result in a Type Ia supernova.

    Lead author Ingrid Pelisoli from the University of Warwick Department of Physics explains: “We don’t know exactly how these supernovae explode, but we know it has to happen because we see it happening elsewhere in the universe.”

    “One way is if the white dwarf accretes enough mass from the hot subdwarf, so as the two of them are orbiting each other and getting closer, matter will start to escape the hot subdwarf and fall onto the white dwarf. Another way is that because they are losing energy to gravitational wave emissions, they will get closer until they merge. Once the white dwarf gains enough mass from either method, it will go supernova,” she says.

    Using data from NASA’s Transiting Exoplanet Survey Satellite, the team was able to observe the hot subdwarf.

    National Aeronautics Space Agency (US)/Massachusetts Institute of Technology (US) TESS

    Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Center for Astrophysics – Harvard and Smithsonian; MIT Lincoln Laboratory; and the NASA Space Telescope Science Institute (US) in Baltimore.

    While they did not detect the white dwarf, the researchers observed the brightness of the hot subdwarf varied over time; this suggests a nearby massive object was distorting the star into a teardrop shape.

    The astronomers then used Palomar Observatory and Keck Observatory’s Echellette Spectrograph and Imager (ESI) [below] to measure the radial velocity and rotational velocity of the hot subdwarf star, which allowed them to confirm that the hidden white dwarf is as heavy as our Sun, but just slightly smaller than the Earth’s radius.

    Combined with the mass of the hot subdwarf, which is a little over 0.6 times the mass of our Sun, both stars have the mass needed to cause a Type Ia supernova.

    “Keck’s ESI data was crucial in determining that the compact binary system exceeds the Chandrasekhar mass limit, which makes HD265435 one of the very few supernova Ia progenitor systems known,” says co-author Thomas Kupfer, assistant professor at Texas Tech University’s (US) Department of Physics and Astronomy.

    As the two stars are already close enough to begin spiraling closer together, the white dwarf will inevitably go supernova in around 70 million years. Theoretical models produced specifically for this study also predict that the hot subdwarf will contract to become a white dwarf star before merging with its companion.

    Type Ia supernovae are important for cosmology as ‘standard candles.’

    Their brightness is constant and of a specific type of light, which means astronomers can compare what luminosity they should be with what we observe on Earth, and from that work out how distant they are with a good degree of accuracy. By observing supernovae in distant galaxies, astronomers combine what they know of how fast this galaxy is moving with our distance from the supernova and calculate the expansion of the universe.

    “The more we understand how supernovae work, the better we can calibrate our standard candles. This is very important at the moment because there’s a discrepancy between what we get from this kind of standard candle, and what we get through other methods,” says Pelisoli.

    She adds, “The more we understand about how supernovae form, the better we can understand whether this discrepancy we are seeing is because of new physics that we’re unaware of and not taking into account, or simply because we’re underestimating the uncertainties in those distances.”

    “There is another discrepancy between the estimated and observed galactic supernovae rate, and the number of progenitors we see. We can estimate how many supernovae are going to be in our galaxy through observing many galaxies, or through what we know from stellar evolution, and this number is consistent. But if we look for objects that can become supernovae, we don’t have enough. This discovery was very useful to put an estimate of what a hot subdwarf and white dwarf binaries can contribute. It still doesn’t seem to be a lot, none of the channels we observed seems to be enough,” Pelisoli says.

    This research was funded by the German Research Foundation -DFG [Deutsche Forschungsgemeinschaft] (DE) and the Science & Technology Facilities Council (UK), part of UKRI – UK Research and Innovation(UK).

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    height=”375″ class=”size-full wp-image-32389″ /> Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope.[/caption]

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.

    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.


    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

     
  • richardmitnick 11:34 am on June 30, 2021 Permalink | Reply
    Tags: "A White Dwarf Living on the Edge", , , , , , The newfound tiny white dwarf named ZTF J1901+1458, W.M. Keck Observatory (US)   

    From W.M. Keck Observatory (US) : “A White Dwarf Living on the Edge”A White Dwarf Living on the Edge” 

    From W.M. Keck Observatory (US)

    6.30.21

    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567

    Astronomers Have Identified A White Dwarf So Massive That It Might Collapse.

    1
    This illustration highlights a newfound small white dwarf that is somewhat larger than earth’s moon. the two bodies are shown next to each other for size comparison. the hot, young white dwarf is the most massive white dwarf known, weighing 1.35 times as much as our sun. Credit: Giuseppe Parisi.

    Astronomers have discovered the smallest and most massive white dwarf ever seen. The smoldering cinder, which formed when two less massive white dwarfs merged, is heavy, “packing a mass greater than that of our Sun into a body about the size of our Moon,” says Ilaria Caiazzo, the Sherman Fairchild Postdoctoral Scholar Research Associate in Theoretical Astrophysics at California Institute of Technology (US) and lead author of the new study appearing in the July 1 issue of the journal Nature. “It may seem counterintuitive, but smaller white dwarfs happen to be more massive. This is due to the fact that white dwarfs lack the nuclear burning that keep up normal stars against their own self gravity, and their size is instead regulate­­­d by quantum mechanics.”

    The discovery was made by the Zwicky Transient Facility, or ZTF, which operates at Caltech’s Palomar Observatory; two Hawaiʻi telescopes – W. M. Keck Observatory on Maunakea, Hawaiʻi Island [above] and University of Hawaiʻi Institute for Astronomy’s Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) on Haleakala, Maui – helped characterize the dead star, along with the 200-inch Hale Telescope at Palomar, the European Gaia space observatory, and NASA’s Neil Gehrels Swift Observatory.

    White dwarfs are the collapsed remnants of stars that were once about eight times the mass of our Sun or lighter.

    Our Sun, for example, after it first puffs up into a red giant in about 5 billion years, will ultimately slough off its outer layers and shrink down into a compact white dwarf. About 97 percent of all stars become white dwarfs.

    While our Sun is alone in space without a stellar partner, many stars orbit around each other in pairs. The stars grow old together, and if they are both less than eight solar-masses, they will both evolve into white dwarfs.

    The new discovery provides an example of what can happen after this phase. The pair of white dwarfs, which spiral around each other, lose energy in the form of gravitational waves and ultimately merge. If the dead stars are massive enough, they explode in what is called a type Ia supernova. But if they are below a certain mass threshold, they combine together into a new white dwarf that is heavier than either progenitor star. This process of merging boosts the magnetic field of that star and speeds up its rotation compared to that of the progenitors.

    Astronomers say that the newfound tiny white dwarf named ZTF J1901+1458, took the latter route of evolution; its progenitors merged and produced a white dwarf 1.35 times the mass of our Sun. The white dwarf has an extreme magnetic field almost 1 billion times stronger than our Sun’s and whips around on its axis at a frenzied pace of one revolution every seven minutes (the zippiest white dwarf known, called EPIC 228939929, rotates every 5.3 minutes).

    “We caught this very interesting object that wasn’t quite massive enough to explode,” says Caiazzo. “We are truly probing how massive a white dwarf can be.”

    What’s more, Caiazzo and her collaborators think that the merged white dwarf may be massive enough to evolve into a neutron-rich dead star, or neutron star, which typically forms when a star much more massive than our Sun explodes in a supernova.

    “This is highly speculative, but it’s possible that the white dwarf is massive enough to further collapse into a neutron star,” says Caiazzo. “It is so massive and dense that, in its core, electrons are being captured by protons in nuclei to form neutrons. Because the pressure from electrons pushes against the force of gravity, keeping the star intact, the core collapses when a large enough number of electrons are removed.”

    If this neutron star formation hypothesis is correct, it may mean that a significant portion of other neutron stars take shape in this way. The newfound object’s close proximity (about 130 light-years away) and its young age (about 100 million years old or less) indicate that similar objects may occur more commonly in our galaxy.

    Magnetic and Fast

    The white dwarf was first spotted by Caiazzo’s colleague Kevin Burdge, a postdoctoral scholar at Caltech, after searching through all-sky images captured by ZTF. This particular white dwarf, when analyzed in combination with data from Gaia, stood out for being very massive and having a rapid rotation.

    “No one has systematically been able to explore short-timescale astronomical phenomena on this kind of scale until now. The results of these efforts are stunning,” says Burdge, who, in 2019, led the team that discovered a pair of white dwarfs zipping around each other every seven minutes.

    The team then analyzed the spectrum of the star using Keck Observatory’s Low Resolution Imaging Spectrometer (LRIS) [below], and that is when Caiazzo was struck by the signatures of a very powerful magnetic field and realized that she and her team had found something “very special,” as she says. The strength of the magnetic field together with the seven-minute rotational speed of the object indicated that it was the result of two smaller white dwarfs coalescing into one.

    Data from Swift, which observes ultraviolet light, helped nail down the size and mass of the white dwarf. With a diameter of 2,670 miles, ZTF J1901+1458 secures the title for the smallest known white dwarf, edging out previous record holders, RE J0317-853 and WD 1832+089, which each have diameters of about 3,100 miles.

    2
    The white dwarf ZTF J1901+1458 is about 2,670 miles across, while the moon is 2,174 miles across. The white dwarf is depicted above the Moon in this artistic representation; in reality, the white dwarf lies 130 light-years away in the constellation of Aquila. Credit: Giuseppe Parisi.

    In the future, Caiazzo hopes to use ZTF to find more white dwarfs like this one, and, in general, to study the population as a whole. “There are so many questions to address, such as what is the rate of white dwarf mergers in the galaxy, and is it enough to explain the number of type Ia supernovae? How is a magnetic field generated in these powerful events, and why is there such diversity in magnetic field strengths among white dwarfs? Finding a large population of white dwarfs born from mergers will help us answer all these questions and more.”

    ABOUT LRIS

    The Low Resolution Imaging Spectrometer (LRIS) is a very versatile and ultra-sensitive visible-wavelength imager and spectrograph built at the California Institute of Technology by a team led by Prof. Bev Oke and Prof. Judy Cohen and commissioned in 1993. Since then it has seen two major upgrades to further enhance its capabilities: the addition of a second, blue arm optimized for shorter wavelengths of light and the installation of detectors that are much more sensitive at the longest (red) wavelengths. Each arm is optimized for the wavelengths it covers. This large range of wavelength coverage, combined with the instrument’s high sensitivity, allows the study of everything from comets (which have interesting features in the ultraviolet part of the spectrum), to the blue light from star formation, to the red light of very distant objects. LRIS also records the spectra of up to 50 objects simultaneously, especially useful for studies of clusters of galaxies in the most distant reaches, and earliest times, of the universe. LRIS was used in observing distant supernovae by astronomers who received the Nobel Prize in Physics in 2011 for research determining that the universe was speeding up in its expansion.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory (US) operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

    Instrumentation

    Keck 1

    HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.

    LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.

    VISIBLE BAND (0.3-1.0 Micron)

    MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.

    OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available.

    Keck 2

    DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.

    NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.

    ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.

    KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.

    NEAR-INFRARED (1-5 Micron)

    ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.

    LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.

    NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.

    ABOUT NIRES
    The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.

    Future Instrumentation

    KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.

    KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.

     
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