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  • richardmitnick 2:25 pm on April 13, 2017 Permalink | Reply
    Tags: Jupiter's icy moon Europa, NASA/ESA Hubble, Probable plume of material erupting   

    From Hubble: “Hubble Spots Possible Venting Activity on Europa” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    Apr 13, 2017

    Felicia Chou
    NASA Headquarters, Washington, D.C.
    202-358-0257
    felicia.chou@nasa.gov

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    William Sparks
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4843
    sparks@stsci.edu

    1
    2
    2014 vs 2016

    Recent observations of Jupiter’s icy moon Europa by NASA’s Hubble Space Telescope have uncovered a probable plume of material erupting from the moon’s surface at precisely the same location as a similar apparent plume seen two years earlier by Hubble. These images bolster evidence that the plumes are a real phenomenon, flaring up intermittently in the same region on the satellite.

    In the most recent observation — Feb. 22, 2016 — Hubble’s Space Telescope Imaging Spectrograph (STIS) uncovered a dark patch, silhouetted against Jupiter and protruding slightly off the surface at Europa’s equatorial region. The dark feature is not only in the same location but is also similar in appearance to the one seen in a previous STIS study of Europa, taken March 17, 2014.

    For both the 2016 and 2014 observations, Sparks and his team used the same transit technique to uncover the plumes in ultraviolet light. As Europa passes in front of Jupiter, any atmospheric features around the edge of the moon block some of Jupiter’s light, allowing STIS to see those features in silhouette.

    Planet transit. NASA/Ames

    The plumes correspond to the location of an unusually warm spot on the moon’s icy crust, seen in the late 1990s by NASA’s Galileo spacecraft.

    NASA/Galileo 1989-2003

    Researchers speculate that this might be circumstantial evidence for water erupting from the moon’s subsurface. Such a “location of interest” may be a site where material dredged up from beneath Europa’s surface could be analyzed for habitability by a future visiting spacecraft.

    “If there is a causal link between the plumes and the thermal anomaly, there could be geologic activity on Europa’s surface that is producing the plumes, or the plume activity may be influencing the surface thermal properties,” said lead researcher William Sparks of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.

    Added team member Britney Schmidt of the Georgia Institute of Technology in Atlanta: “This latest observation adds to the growing evidence that Europa’s complex geology belies an active, maybe habitable, ice shell and ocean. Understanding Europa’s plumbing through studies like this gives us a chance to better understand that picture.”

    The newly imaged plume rises about 62 miles above Europa’s surface. The plume observed by Hubble in 2014 in the same location was estimated to be about 30 miles high.

    Sparks’ team matched the plumes’ position with their corresponding location on the thermal map taken of the moon’s night side by Galileo. The absence of sunlight at night allows Europa’s surface to cool down. But the researchers spotted a region that was warmer than the surrounding area. This region, roughly 200 miles across, is in the same location as the observed plumes. The area was previously identified as a “thermal anomaly,” because it was a few degrees warmer than the surrounding terrain. Such an apparently minor temperature variation is significant, considering that Europa’s icy surface is so cold.

    One possibility for the temperature variation is that an infusion of energy warmed up the frigid surface. Another idea is that the surface retains an abnormal amount of heat. Both possibilities suggest that unusual activity is taking place.

    “After Hubble imaged the second plume-like feature, we looked at its corresponding location on the thermal map, because studies of the plumes on Saturn’s moon Enceladus have shown that they are associated with hotter regions,” Sparks explained. “We discovered that Europa’s plume candidate is sitting right on the thermal anomaly.”

    The plumes and the warm spot could be generated by a variety of geological activity. The team has proposed two possible scenarios for a link between the two features.

    The warmer area could be caused by the heat from liquid water, located more than one mile beneath Europa’s thick, icy crust. The water is pushed upward and cracks the surface, venting as a plume.

    Another idea is that water ejected by the plume falls onto the surface as a fine mist. This process could change the structure of the surface grains, allowing them to retain heat longer than the surrounding landscape.

    Sparks and his team are continuing to use Hubble to search for additional examples of plume candidates on Europa, hoping to determine the frequency with which they appear.

    The results will appear on April 13, 2017, in The Astrophysical Journal Letters.

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

    See the full article here .

    Please help promote STEM in your local schools.

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 12:31 pm on March 23, 2017 Permalink | Reply
    Tags: , , , , Hubble detects supermassive black hole kicked out of galactic core, NASA/ESA Hubble,   

    From ESA/Hubble: “Hubble detects supermassive black hole kicked out of galactic core”and from NASA/HubbleSite “Gravitational Wave Kicks Monster Black Hole Out Of Galactic Core “ 

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    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    From ESA/Hubble

    “Hubble detects supermassive black hole kicked out of galactic core”

    23 March 2017
    Marco Chiaberge
    Space Telescope Science Institute
    Baltimore, USA
    Tel: +1 410 338 4980
    Email: chiab@stsci.edu

    Stefano Bianchi
    Roma Tre University
    Rome, Italy
    Tel: +39 657337241
    Email: bianchi@fis.uniroma3.it

    Mathias Jäger
    ESA/Hubble, Public Information Officer
    Garching bei München, Germany
    Cell: +49 17662397500
    Email: mjaeger@partner.eso.org

    1
    The galaxy 3C186, located about 8 billion years from Earth, is most likely the result of a merger of two galaxies. This is supported by arc-shaped tidal tails, usually produced by a gravitational tug between two colliding galaxies, identified by the scientists. The merger of the galaxies also led to a merger of the two supermassive black holes in their centres, and the resultant black hole was then kicked out of its parent galaxy by the gravitational waves created by the merger. The bright, star-like looking quasar can be seen in the centre of the image. Its former host galaxy is the faint, extended object behind it. Credit: NASA, ESA, and M. Chiaberge (STScI/ESA)

    2
    An international team of astronomers using the NASA/ESA Hubble Space Telescope have uncovered a supermassive black hole that has been propelled out of the centre of the distant galaxy 3C186. The black hole was most likely ejected by the power of gravitational waves. This is the first time that astronomers found a supermassive black hole at such a large distance from its host galaxy centre.

    Though several other suspected runaway black holes have been seen elsewhere, none has so far been confirmed. Now astronomers using the NASA/ESA Hubble Space Telescope have detected a supermassive black hole, with a mass of one billion times the Sun’s, being kicked out of its parent galaxy. “We estimate that it took the equivalent energy of 100 million supernovae exploding simultaneously to jettison the black hole,” describes Stefano Bianchi, co-author of the study, from the Roma Tre University, Italy.

    The images taken by Hubble provided the first clue that the galaxy, named 3C186, was unusual. The images of the galaxy, located 8 billion light-years away, revealed a bright quasar, the energetic signature of an active black hole, located far from the galactic core. “Black holes reside in the centres of galaxies, so it’s unusual to see a quasar not in the centre,” recalls team leader Marco Chiaberge, ESA-AURA researcher at the Space Telescope Science Institute, USA.

    The team calculated that the black hole has already travelled about 35 000 light-years from the centre, which is more than the distance between the Sun and the centre of the Milky Way. And it continues its flight at a speed of 7.5 million kilometres per hour [1]. At this speed the black hole could travel from Earth to the Moon in three minutes.

    Although other scenarios to explain the observations cannot be excluded, the most plausible source of the propulsive energy is that this supermassive black hole was given a kick by gravitational waves [2] unleashed by the merger of two massive black holes at the centre of its host galaxy. This theory is supported by arc-shaped tidal tails identified by the scientists, produced by a gravitational tug between two colliding galaxies.

    According to the theory presented by the scientists, 1-2 billion years ago two galaxies — each with central, massive black holes — merged. The black holes whirled around each other at the centre of the newly-formed elliptical galaxy, creating gravitational waves that were flung out like water from a lawn sprinkler [3]. As the two black holes did not have the same mass and rotation rate, they emitted gravitational waves more strongly along one direction. When the two black holes finally merged, the anisotropic emission of gravitational waves generated a kick that shot the resulting black hole out of the galactic centre.

    “If our theory is correct, the observations provide strong evidence that supermassive black holes can actually merge,” explains Stefano Bianchi on the importance of the discovery. “There is already evidence of black hole collisions for stellar-mass black holes, but the process regulating supermassive black holes is more complex and not yet completely understood.”

    The researchers are lucky to have caught this unique event because not every black hole merger produces imbalanced gravitational waves that propel a black hole out of the galaxy. The team now wants to secure further observation time with Hubble, in combination with the Atacama Large Millimeter/submillimeter Array (ALMA) and other facilities, to more accurately measure the speed of the black hole and its surrounding gas disc, which may yield further insights into the nature of this rare object.
    Notes

    [1] As the black hole cannot be observed directly, the mass and the speed of the supermassive black holes were determined via spectroscopic analysis of its surrounding gas.

    [2] First predicted by Albert Einstein, gravitational waves are ripples in space that are created by accelerating massive objects. The ripples are similar to the concentric circles produced when a rock is thrown into a pond. In 2016, the Laser Interferometer Gravitational-wave Observatory (LIGO) helped astronomers prove that gravitational waves exist by detecting them emanating from the union of two stellar-mass black holes, which are several times more massive than the Sun.

    [3] The black holes get closer over time as they radiate away gravitational energy.

    The international team of astronomers in this study consists of Marco Chiaberge (STScI, USA; Johns Hopkins University, USA), Justin C. Ely (STScI, USA), Eileen Meyer (University of Maryland Baltimore County, USA), Markos Georganopoulos (University of Maryland Baltimore County, USA; NASA Goddard Space Flight Center, USA), Andrea Marinucci (Università degli Studi Roma Tre, Italy), Stefano Bianchi (Università degli Studi Roma Tre, Italy), Grant R. Tremblay (Yale University, USA), Brian Hilbert (STScI, USA), John Paul Kotyla (STScI, USA), Alessandro Capetti (INAF – Osservatorio Astrofisico di Torino, Italy), Stefi Baum (University of Manitoba, Canada), F. Duccio Macchetto (STScI, USA), George Miley (University of Leiden, Netherlands), Christopher O’Dea (University of Manitoba, Canada), Eric S. Perlman (Florida Institute of Technology, USA), William B. Sparks (STScI, USA) and Colin Norman (STScI, USA; Johns Hopkins University, USA)

    Image credit: NASA, ESA, M. Chiaberge (STScI/ESA)

    Science paper:
    The puzzling case of the radio-loud QSO 3C 186: a gravitational wave recoiling black hole in a young radio source?

    From NASA HubbleSite

    “Gravitational Wave Kicks Monster Black Hole Out Of Galactic Core “

    Mar 23, 2017

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Marco Chiaberge
    Space Telescope Science Institute and
    The Johns Hopkins University, Baltimore, Maryland
    410-338-4980
    marcoc@stsci.edu

    3
    Runaway black hole is the most massive ever detected far from its central home
    Normally, hefty black holes anchor the centers of galaxies. So researchers were surprised to discover a supermassive black hole speeding through the galactic suburbs. Black holes cannot be observed directly, but they are the energy source at the heart of quasars — intense, compact gushers of radiation that can outshine an entire galaxy. NASA’s Hubble Space Telescope made the discovery by finding a bright quasar located far from the center of the host galaxy.

    Researchers estimate that it took the equivalent energy of 100 million supernovas exploding simultaneously to jettison the black hole. What could pry this giant monster from its central home? The most plausible explanation for this propulsive energy is that the monster object was given a kick by gravitational waves unleashed by the merger of two black holes as a result of a collision between two galaxies. First predicted by Albert Einstein, gravitational waves are ripples in the fabric of space that are created when two massive objects collide.

    The Full [HubbleSite] Story

    Astronomers have uncovered a supermassive black hole that has been propelled out of the center of a distant galaxy by what could be the awesome power of gravitational waves.

    Though there have been several other suspected, similarly booted black holes elsewhere, none has been confirmed so far. Astronomers think this object, detected by NASA’s Hubble Space Telescope, is a very strong case. Weighing more than 1 billion suns, the rogue black hole is the most massive black hole ever detected to have been kicked out of its central home.

    Researchers estimate that it took the equivalent energy of 100 million supernovas exploding simultaneously to jettison the black hole. The most plausible explanation for this propulsive energy is that the monster object was given a kick by gravitational waves unleashed by the merger of two hefty black holes at the center of the host galaxy.

    First predicted by Albert Einstein, gravitational waves are ripples in space that are created when two massive objects collide. The ripples are similar to the concentric circles produced when a hefty rock is thrown into a pond. Last year, the Laser Interferometer Gravitational-Wave Observatory (LIGO) helped astronomers prove that gravitational waves exist by detecting them emanating from the union of two stellar-mass black holes, which are several times more massive than the sun.

    Hubble’s observations of the wayward black hole surprised the research team. “When I first saw this, I thought we were seeing something very peculiar,” said team leader Marco Chiaberge of the Space Telescope Science Institute (STScI) and Johns Hopkins University, in Baltimore, Maryland. “When we combined observations from Hubble, the Chandra X-ray Observatory, and the Sloan Digital Sky Survey, it all pointed towards the same scenario. The amount of data we collected, from X-rays to ultraviolet to near-infrared light, is definitely larger than for any of the other candidate rogue black holes.”

    Chiaberge’s paper will appear in the March 30 issue of Astronomy & Astrophysics.

    Hubble images taken in visible and near-infrared light provided the first clue that the galaxy was unusual. The images revealed a bright quasar, the energetic signature of a black hole, residing far from the galactic core. Black holes cannot be observed directly, but they are the energy source at the heart of quasars – intense, compact gushers of radiation that can outshine an entire galaxy. The quasar, named 3C 186, and its host galaxy reside 8 billion light-years away in a galaxy cluster. The team discovered the galaxy’s peculiar features while conducting a Hubble survey of distant galaxies unleashing powerful blasts of radiation in the throes of galaxy mergers.

    “I was anticipating seeing a lot of merging galaxies, and I was expecting to see messy host galaxies around the quasars, but I wasn’t really expecting to see a quasar that was clearly offset from the core of a regularly shaped galaxy,” Chiaberge recalled. “Black holes reside in the center of galaxies, so it’s unusual to see a quasar not in the center.”

    The team calculated the black hole’s distance from the core by comparing the distribution of starlight in the host galaxy with that of a normal elliptical galaxy from a computer model. The black hole had traveled more than 35,000 light-years from the center, which is more than the distance between the sun and the center of the Milky Way.

    Based on spectroscopic observations taken by Hubble and the Sloan survey, the researchers estimated the black hole’s mass and measured the speed of gas trapped near the behemoth object. Spectroscopy divides light into its component colors, which can be used to measure velocities in space. “To our surprise, we discovered that the gas around the black hole was flying away from the galaxy’s center at 4.7 million miles an hour,” said team member Justin Ely of STScI. This measurement is also a gauge of the black hole’s velocity, because the gas is gravitationally locked to the monster object.

    The astronomers calculated that the black hole is moving so fast it would travel from Earth to the moon in three minutes. That’s fast enough for the black hole to escape the galaxy in 20 million years and roam through the universe forever.

    The Hubble image revealed an interesting clue that helped explain the black hole’s wayward location. The host galaxy has faint arc-shaped features called tidal tails, produced by a gravitational tug between two colliding galaxies. This evidence suggests a possible union between the 3C 186 system and another galaxy, each with central, massive black holes that may have eventually merged.

    Based on this visible evidence, along with theoretical work, the researchers developed a scenario to describe how the behemoth black hole could be expelled from its central home. According to their theory, two galaxies merge, and their black holes settle into the center of the newly formed elliptical galaxy. As the black holes whirl around each other, gravity waves are flung out like water from a lawn sprinkler. The hefty objects move closer to each other over time as they radiate away gravitational energy. If the two black holes do not have the same mass and rotation rate, they emit gravitational waves more strongly along one direction. When the two black holes collide, they stop producing gravitational waves. The newly merged black hole then recoils in the opposite direction of the strongest gravitational waves and shoots off like a rocket.

    The researchers are lucky to have caught this unique event because not every black-hole merger produces imbalanced gravitational waves that propel a black hole in the opposite direction. “This asymmetry depends on properties such as the mass and the relative orientation of the back holes’ rotation axes before the merger,” said team member Colin Norman of STScI and Johns Hopkins University. “That’s why these objects are so rare.”

    An alternative explanation for the offset quasar, although unlikely, proposes that the bright object does not reside within the galaxy. Instead, the quasar is located behind the galaxy, but the Hubble image gives the illusion that it is at the same distance as the galaxy. If this were the case, the researchers should have detected a galaxy in the background hosting the quasar.

    If the researchers’ interpretation is correct, the observations may provide strong evidence that supermassive black holes can actually merge. Astronomers have evidence of black-hole collisions for stellar-mass black holes, but the process regulating supermassive black holes is more complex and not completely understood.

    The team hopes to use Hubble again, in combination with the Atacama Large Millimeter/submillimeter Array (ALMA) and other facilities, to more accurately measure the speed of the black hole and its gas disk, which may yield more insight into the nature of this bizarre object.

    See the full ESA article here .

    See the full NASA HubbleSite story here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 4:07 pm on March 1, 2017 Permalink | Reply
    Tags: , , , , NASA/ESA Hubble, The 20th Anniversary of the Hubble Space Telescope’s STIS Instrument   

    From Hubble: “The 20th Anniversary of the Hubble Space Telescope’s STIS Instrument” 

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    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    Happy 20th birthday to Hubble’s Space Telescope Imaging Spectrograph (STIS)! In February 1997, astronauts installed STIS on the telescope during the second servicing mission. The highly versatile and productive instrument combines a camera with a spectrograph, which separates light into its component colors—or wavelengths — to provide a “fingerprint” of the object being observed. This tells us about the object’s temperature, chemical composition, density, and motion. Spectrographic observations also reveal changes in celestial objects as the universe evolves. STIS has also pioneered the field of high-contrast imaging—the art of capturing faint objects (such as planets, disks, and outflowing jets) next to very bright ones (such as the stars they accompany). The instrument is sensitive to a wide range of wavelengths of light, from ultraviolet through the optical and into the near-infrared. STIS science has illuminated a multitude of different astronomical topics. Below are some examples, but this is not meant to be an exhaustive list.

    1

    Determining the Masses of Black Holes in the Centers of Galaxies

    Astronomers used STIS to conduct a census of more than 30 galaxies to look for evidence of massive black holes at their centers. STIS precisely measures the speed of gas and stars around a black hole, and this yields information about its mass. The findings presented a broad picture of a galaxy’s evolution and its relationship to the growth of the massive central black hole. Hubble evidence favors the idea that titanic black holes did not precede a galaxy’s birth, but instead co-evolved with the galaxy by trapping a surprisingly exact proportion of the mass of the central hub of stars and gas in that galaxy.

    Tracing the Evolution of the Intergalactic Medium

    Astronomers have long sought the vast quantities of hydrogen that were cooked up in the Big Bang but that somehow seemingly managed to disappear. This gas accounts for nearly half of the “normal” matter in the universe—the rest is locked up in galaxies. In an extensive search of the nearby universe, astronomers using STIS have definitively found this missing matter in the space between the galaxies. Called the intergalactic medium, this space extends from just outside our Milky Way galaxy to the most distant regions of space observed by astronomers. STIS observations of the local intergalactic medium showed that the missing hydrogen is still out there in very diffuse clouds in between the galaxies. This confirmation sheds new light on the large-scale structure of the universe and provides information on how galaxies built up over time. It also confirms fundamental models of how so much hydrogen was manufactured in the first few minutes of the universe’s birth in the Big Bang.

    Understanding the Components of the Galactic Halo

    A halo of very hot gas surrounds the Milky Way galaxy. Because the gas is so highly energized, or ionized, it is only visible in spectral features seen in ultraviolet wavelengths with an instrument like STIS. With its extremely high spectral resolution, STIS looks at the spectral features of the atoms in each of the many layers of gas to help scientists identify and understand the complexity of the halo structure. Besides the very hot gas that is trapped in the halo, some gas is falling into the Milky Way from the area between galaxies, known as the intergalactic medium. Other gas in the halo comes from star formation in the disk of the Milky Way. Supernovae and winds from stars can blow this material out of the plane of the Milky Way, up into the Galactic halo. This gas cools and gets denser, and some of it rains back down in what is often described as “the Galactic fountain.” STIS helps scientists understand these complex processes.

    Unraveling the Structure of the Interstellar Medium

    The interstellar medium is everything between the stars. It’s typically very low-density material, which is extremely difficult to study. With its ultraviolet sensitivity and exceedingly high spectral resolution, STIS is a premier instrument for understanding this space. Scientists use stars or other bright sources as background light to view the intervening material. They “see” it indirectly through the absorption of the background light. The interstellar medium is not entirely uniform. There are places it is denser, places where it is less dense, and different clumps move at different velocities. STIS provides the fine velocity information to analyze the details of the interstellar medium. Using STIS, scientists can determine the physical conditions and separate out components from different densities and types of gas along the line of sight.

    Characterizing the Atmosphere of a World around Another Star

    Astronomers using STIS made the first direct chemical analysis of the atmosphere of a planet orbiting another star. This opened up an exciting new phase of extrasolar planet exploration, where astronomers can compare and contrast the atmospheres of planets around other stars, and search for chemical biomarkers of life beyond Earth. The planet orbits a sun-like star called HD 209458. Its atmospheric composition was probed when the planet passed in front of its parent star, allowing astronomers for the first time ever to see light from the star filtered through the planet’s atmosphere. Scientists detected the presence of sodium in the planet’s atmosphere. They actually saw less sodium than predicted for the Jupiter-class planet, leading to one interpretation that high-altitude clouds in the alien atmosphere may have blocked some of the light.

    Imaging the Dust Disk around Beta Pictoris

    In 1984, Beta Pictoris was the first star discovered to host a bright disk of light-scattering circumstellar dust and debris. Ever since then, the 20-million-year-old star has been an object of intense scrutiny with Hubble and with ground-based telescopes. Astronomers used STIS in 1997 and 2012 to take the most detailed pictures to date of the large, edge-on, gas-and-dust disk. Astronomers found that the disk’s dust distribution had barely changed over 15 years, despite the fact that the entire structure is orbiting the star like a carousel.

    Finding Evidence for Water on Jupiter’s Moons

    Identifying liquid water on other worlds is crucial in the search for habitable planets beyond Earth. STIS imaging shows suspected water plumes erupting from Jupiter’s icy moon Europa. Astronomers observed these finger-like projections while viewing Europa’s limb as the moon passed in front of Jupiter. Europa is a plausible place for life to have developed beyond Earth. If the venting plumes originate in a subsurface ocean, they could act as an elevator to bring deep-sea water above Europa’s surface, where visiting spacecraft could sample it, study its habitability, and even look for life. This offers a convenient way to access the chemistry of that ocean without drilling through miles of ice.

    STIS also revealed that another Jovian moon, Ganymede, may contain a subsurface ocean. STIS found evidence for it by watching aurorae glowing above the moon’s icy surface. The aurorae are tied to the moon’s magnetic field, which descends to the core of Ganymede. A saline ocean would influence the dynamics of the magnetic field as it interacts with Jupiter’s own immense magnetic field, which engulfs Ganymede. Because telescopes can’t look inside planets or moons, tracing the magnetic field through aurorae is a unique way to probe the interior of another world.

    Detecting Monster Stars in a Massive Star Cluster

    R136 is a very massive and young dense star cluster in the Tarantula Nebula within the Large Magellanic Cloud, a neighboring galaxy to our Milky Way. Only Hubble can resolve the individual stars in the dense core, which is only a few light-years across and less than 2 million years old. Astronomers used STIS to obtain ultraviolet spectra of the individual hot luminous stars in the core and showed in 2016 that there are nine stars with masses over 100 times the mass of the sun. The detected stars are not only extremely massive, but also extremely bright. Together these nine stars outshine the sun by a factor of 30 million. This discovery has led astronomers to examine the 20 years’ worth of STIS observations available in the Mikulski Archive for Space Telescopes (MAST) for further examples of monster stars in more distant star clusters. Some have recently been found in the dwarf galaxy NGC 5253, and the search continues for more examples.

    Unlocking the Secrets of the Massive Star Eta Carinae

    The volatile, erupting pair of massive stars called Eta Carinae has long intrigued astronomers. In 2009, STIS analyzed the ejecta from an eruption seen in the late nineteenth century, resolving the chemical information along a narrow section close to the binary. The resulting spectrum showed iron and nickel that had been cast off in the nineteenth century. STIS also revealed the interior material being carried away by the ongoing, colliding winds from Eta Car A, the primary star, and those of Eta Car B, a hotter, less massive star. A very faint structure, seen in argon, is evidence of the interacting winds excited by ultraviolet radiation from Eta Car B. Eta Car A is one of the most massive and luminous stars visible in the night sky. Because of the star’s extremely high mass, it is unstable and uses its fuel very quickly, compared with other stars. Such massive stars also have short lifetimes, and astronomers expect that Eta Carinae will explode as a supernova within a hundred thousand years.

    Deciphering the Composition of Supernova 1987A

    Thirty years ago, astronomers witnessed one of the brightest stellar explosions seen from Earth in more than 400 years. The titanic supernova, called SN 1987A, blazed with the power of 100 million suns for several months following its discovery on February 23, 1987. Ten years later, STIS provided an unprecedented look at the light-year-wide ring of glowing gas surrounding SN 1987A. The long-slit spectrograph viewed the entire ring system, dissecting its light and producing a detailed image of the ring in each of its component colors that correspond to nitrogen, hydrogen, and sulfur. By dividing the ring into its component elements, astronomers put together a picture of how the ring was created.

    Measuring the Outflow from the Heart of an Active Galaxy

    STIS measured the velocities of hundreds of gas knots streaming at hundreds of thousands of miles per hour from the nucleus of galaxy NGC 4151, thought to host a supermassive black hole. This was the first time the velocity structure in the heart of an active galaxy was mapped so precisely so close to its central black hole.

    For more information on the Hubble mission and the servicing missions that made STIS possible, you can visit:
    http://www.nasa.gov/hubble

    For more Hubble images, educational activities, and resources, visit
    http://www.hubblesite.org

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 2:29 pm on February 18, 2017 Permalink | Reply
    Tags: , , , , Hubble Spotlights a Celestial Sidekick, NASA/ESA Hubble   

    From Hubble: “Hubble Spotlights a Celestial Sidekick” 

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    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    Feb. 17, 2017
    Image credit: ESA/Hubble & NASA
    Text Credit: European Space Agency
    Last Updated: Feb. 17, 2017
    Editor: Karl Hille

    1

    This image was captured by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS), a highly efficient wide-field camera covering the optical and near-infrared parts of the spectrum. While this lovely image contains hundreds of distant stars and galaxies, one vital thing is missing — the object Hubble was actually studying at the time!

    This is not because the target has disappeared. The ACS actually uses two detectors: the first captures the object being studied — in this case an open star cluster known as NGC 299 — while the other detector images the patch of space just ‘beneath’ it. This is what can be seen here.

    Technically, this picture is merely a sidekick of the actual object of interest — but space is bursting with activity, and this field of bright celestial bodies offers plenty of interest on its own. It may initially seem to show just stars, but a closer look reveals many of these tiny objects to be galaxies. The spiral galaxies have arms curving out from a bright center. The fuzzier, less clearly shaped galaxies might be ellipticals. Some of these galaxies contain millions or even billions of stars, but are so distant that all of their starry residents are contained within just a small pinprick of light that appears to be the same size as a single star!

    The bright blue dots are very hot stars, sometimes distorted into crosses by the struts supporting Hubble’s secondary mirror. The redder dots are cooler stars, possibly in the red giant phase when a dying star cools and expands.

    See the full article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 3:10 pm on January 7, 2017 Permalink | Reply
    Tags: Hubble Captures 'Shadow Play' Caused by Possible Planet, NASA/ESA Hubble,   

    From Hubble: “Hubble Captures ‘Shadow Play’ Caused by Possible Planet” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    1
    Shadow on TW Hydrae’s Disk

    Felicia Chou
    NASA Headquarters, Washington, D.C.
    202-358-0257
    felicia.chou@nasa.gov

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    John Debes
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4782
    debes@stsci.edu

    Searching for planets around other stars is a tricky business. They’re so small and faint that it’s hard to spot them. But a possible planet in a nearby stellar system may be betraying its presence in a unique way: by a shadow that is sweeping across the face of a vast pancake-shaped gas-and-dust disk surrounding a young star.

    The planet itself is not casting the shadow. But it is doing some heavy lifting by gravitationally pulling on material near the star and warping the inner part of the disk. The twisted, misaligned inner disk is casting its shadow across the surface of the outer disk.

    A team of astronomers led by John Debes of the Space Telescope Science Institute in Baltimore, Maryland, say this scenario is the most plausible explanation for the shadow they spotted in the stellar system TW Hydrae, located 192 light-years away in the constellation Hydra, also known as the Female Water Snake. The star is roughly 8 million years old and slightly less massive than our sun. The researchers uncovered the phenomenon while analyzing 18 years’ worth of archival observations taken by NASA’s Hubble Space Telescope.

    “This is the very first disk where we have so many images over such a long period of time, therefore allowing us to see this interesting effect,” Debes said. “That gives us hope that this shadow phenomenon may be fairly common in young stellar systems.”

    Debes will present his team’s results Jan. 7 at the winter meeting of the American Astronomical Society in Grapevine, Texas.

    Debes’ first clue to the phenomenon was a brightness in the disk that changed with position. Astronomers using Hubble’s Space Telescope Imaging Spectrograph (STIS) first noted this brightness asymmetry in 2005. But they had only one set of observations, and could not make a definitive determination about the nature of the mystery feature.

    Searching the archive, Debes’ team put together six images from several different epochs. The observations were made by STIS and by Hubble’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS).

    STIS is equipped with a coronagraph that blocks starlight to within about 1 billion miles from the star, allowing Hubble to look as close to the star as Saturn is to our sun. Over time, the structure appeared to move in counterclockwise fashion around the disk, until, in 2016, it was in the same position as it was in images taken in 2000.

    This 16-year period puzzled the researchers. They originally thought the feature was part of the disk, but the short period meant that the feature was moving way too fast to be physically in the disk. Under the laws of gravity, disks rotate at glacial speeds. The outermost parts of the TW Hydrae disk would take centuries to complete one rotation.

    “The fact that I saw the same motion over 10 billion miles from the star was pretty significant, and told me that I was seeing something that was imprinted on the outer disk rather than something that was happening directly in the disk itself,” Debes said. “The best explanation is that the feature is a shadow moving across the surface of the disk.”

    The research team concluded that whatever was making the shadow must be deep inside the 41-billion-mile-wide disk, so close to the star it cannot be imaged by Hubble or any other present-day telescope. The most likely way to create a shadow is to have an inner disk that is tilted relative to the outer disk. In fact, submillimeter observations of TW Hydrae by the Atacama Large Millimeter Array (ALMA) in Chile suggested a possible warp in the inner disk.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    But what causes disks to warp? “The most plausible scenario is the gravitational influence of an unseen planet, which is pulling material out of the plane of the disk and twisting the inner disk,” Debes explained. “The misaligned disk is inside the planet’s orbit.”

    Given the relatively short 16-year period of the clocklike moving shadow, the planet is estimated to be about 100 million miles from the star — about as close as Earth is from the sun. The planet would be roughly the size of Jupiter to have enough gravity to pull the material up out of the plane of the main disk. The planet’s gravitational pull causes the disk to wobble, or precess, around the star, giving the shadow its 16-year rotational period.

    Recent observations of TW Hydrae by ALMA in Chile add credence to the presence of a planet. ALMA revealed a gap in the disk roughly 9 million miles from TW Hydrae. A gap is significant, because it could be the signature of an unseen planet clearing away a path in the disk.

    This new Hubble study offers a unique way to look for planets hiding in the inner part of the disk and probe what is happening very close to the star, which is not reachable in direct imaging by current telescopes. “What is surprising is that we can learn something about an unseen part of the disk by studying the disk’s outer region and by measuring the motion, location, and behavior of a shadow,” Debes said. “This study shows us that even these large disks, whose inner regions are unobservable, are still dynamic, or changing in detectable ways which we didn’t imagine.”

    See the full article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 9:19 am on September 7, 2016 Permalink | Reply
    Tags: Astronomers Discover Rare Fossil Relic of Early Milky Way, , , , , NASA/ESA Hubble, Terzan 5   

    From ESO and Hubble: “Astronomers Discover Rare Fossil Relic of Early Milky Way” 

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    7 September 2016
    Francesco Ferraro
    Università degli Studi di Bologna
    Bologna, Italy
    Tel: +39 051 20 9 5774
    Email: francesco.ferraro3@unibo.it

    Davide Massari
    INAF – Osservatorio Astronomico di Bologna
    Bologna, Italy
    Tel: +51 2095318
    Email: davide.massari@oabo.inaf.it

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Mathias Jäger
    ESA/Hubble, Public Information Officer
    Garching bei München, Germany
    Tel: +49 176 62397500
    Email: mjaeger@partner.eso.org

    1

    Using ESO’s Very Large Telescope and other telescopes a fossilised remnant of the early Milky Way harbouring stars of hugely different ages has been revealed by an international team of astronomers. This stellar system resembles a globular cluster, but is like no other cluster known. It contains stars remarkably similar to the most ancient stars in the Milky Way and bridges the gap in understanding between our galaxy’s past and its present.

    Terzan 5, 19 000 light-years from Earth in the constellation of Sagittarius (the Archer) and in the direction of the galactic centre, has been classified as a globular cluster for the forty-odd years since its detection. Now, an Italian-led team of astronomers have discovered that Terzan 5 is like no other globular cluster known.

    The team scoured data from the Multi-conjugate Adaptive Optics Demonstrator [MAD] [1], installed at the Very Large Telescope, as well as from a suite of other ground-based and space telescopes [2]. They found compelling evidence that there are two distinct kinds of stars in Terzan 5 which not only differ in the elements they contain, but have an age-gap of roughly 7 billion years [3].

    ESO MAD bench
    ESO MAD

    The ages of the two populations indicate that the star formation process in Terzan 5 was not continuous, but was dominated by two distinct bursts of star formation. “This requires the Terzan 5 ancestor to have large amounts of gas for a second generation of stars and to be quite massive. At least 100 million times the mass of the Sun,” explains Davide Massari, co-author of the study, from INAF, Italy, and the University of Groningen, Netherlands.

    Its unusual properties make Terzan 5 the ideal candidate for a living fossil from the early days of the Milky Way. Current theories on galaxy formation assume that vast clumps of gas and stars interacted to form the primordial bulge of the Milky Way, merging and dissolving in the process.

    “We think that some remnants of these gaseous clumps could remain relatively undisrupted and keep existing embedded within the galaxy,” explains Francesco Ferraro from the University of Bologna, Italy, and lead author of the study. “Such galactic fossils allow astronomers to reconstruct an important piece of the history of our Milky Way.”

    While the properties of Terzan 5 are uncommon for a globular cluster, they are very similar to the stellar population which can be found in the galactic bulge, the tightly packed central region of the Milky Way. These similarities could make Terzan 5 a fossilised relic of galaxy formation, representing one of the earliest building blocks of the Milky Way.

    This assumption is strengthened by the original mass of Terzan 5 necessary to create two stellar populations: a mass similar to the huge clumps which are assumed to have formed the bulge during galaxy assembly around 12 billion years ago. Somehow Terzan 5 has managed to survive being disrupted for billions of years, and has been preserved as a remnant of the distant past of the Milky Way.

    “Some characteristics of Terzan 5 resemble those detected in the giant clumps we see in star-forming galaxies at high-redshift, suggesting that similar assembling processes occurred in the local and in the distant Universe at the epoch of galaxy formation,“ continues Ferraro.

    Hence, this discovery paves the way for a better and more complete understanding of galaxy assembly. “Terzan 5 could represent an intriguing link between the local and the distant Universe, a surviving witness of the Galactic bulge assembly process,” explains Ferraro while commenting on the importance of the discovery. The research presents a possible route for astronomers to unravel the mysteries of galaxy formation, and offers an unrivaled view into the complicated history of the Milky Way.
    Notes

    [1] The Multi-Conjugate Adaptive Optics Demonstrator (MAD) is a prototype multi-conjugate adaptive optics system which aims to demonstrate the feasibility of different MCAO reconstruction techniques in the framework of the E-ELT concept and the second generation VLT Instruments.

    [2] The researchers also used data from the Advanced Camera for Surveys [ACS]and the Wide Field Camera 3 [WFC3] on board the NASA/ESA Hubble Space Telescope and NIRC2 (the Near-Infrared Camera, second generation) at the W. M. Keck Observatory.

    NASA/ESA Hubble ACS
    “NASA/ESA Hubble ACS

    NASA Hubble WFC3
    NASA/ESA Hubble WFC3

    Keck Observatory, Mauna Kea, Hawaii, USA
    Keck Observatory, Mauna Kea, Hawaii, USA

    Keck NIRC2 Camera
    Keck NIRC2 Camera

    [3] The two detected stellar populations have ages of 12 billion years and 4.5 billion years respectively.

    More information

    Link to science paper.

    The team is composed of F. R. Ferraro (Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Italy) , D. Massari (INAF – Osservatorio Astronomico di Bologna, Italy & Kapteyn Astronomical Institute, University of Groningen, Netherlands), E. Dalessandro (Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Italy; INAF – Osservatorio Astronomico di Bologna, Italy) , B. Lanzoni (Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Italy), L. Origlia (INAF – Osservatorio Astronomico di Bologna, Italy), R. M. Rich (Department of Physics and Astronomy, University of California, Los Angeles, USA) and A. Mucciarelli (Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Italy).

    See the full ESO article here .

    See the full Hubble article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

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  • richardmitnick 2:18 pm on June 23, 2016 Permalink | Reply
    Tags: , , Dark vortex on Neptune, NASA/ESA Hubble   

    From Hubble: “Hubble Confirms New Dark Spot on Neptune” 

    NASA Hubble Banner

    NASA Hubble Telescope

    Hubble

    June 23, 2016
    Donna Weaver / Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493 / 410-338-4514
    dweaver@stsci.edu / villard@stsci.edu

    Robert Sanders
    University of California, Berkeley, California
    510-643-6998
    rlsanders@berkeley.edu

    Mike Wong
    University of California, Berkeley, California
    mikewong@astro.berkeley.edu

    New images obtained on May 16, 2016, by NASA’s Hubble Space Telescope confirm the presence of a dark vortex in the atmosphere of Neptune. Though similar features were seen during the Voyager 2 flyby of Neptune in 1989 and by the Hubble Space Telescope in 1994, this vortex is the first one observed on Neptune in the 21st century.

    1

    The discovery was announced on May 17, 2016, in a Central Bureau for Astronomical Telegrams (CBAT) electronic telegram by University of California at Berkeley research astronomer Mike Wong, who led the team that analyzed the Hubble data.

    Neptune’s dark vortices are high-pressure systems and are usually accompanied by bright “companion clouds,” which are also now visible on the distant planet. The bright clouds form when the flow of ambient air is perturbed and diverted upward over the dark vortex, causing gases to likely freeze into methane ice crystals. “Dark vortices coast through the atmosphere like huge, lens-shaped gaseous mountains,” Wong said. “And the companion clouds are similar to so-called orographic clouds that appear as pancake-shaped features lingering over mountains on Earth.”

    Beginning in July 2015, bright clouds were again seen on Neptune by several observers, from amateurs to astronomers at the W. M. Keck Observatory in Hawaii. Astronomers suspected that these clouds might be bright companion clouds following an unseen dark vortex. Neptune’s dark vortices are typically only seen at blue wavelengths, and only Hubble has the high resolution required for seeing them on distant Neptune.

    In September 2015, the Outer Planet Atmospheres Legacy (OPAL) program, a long-term Hubble Space Telescope project that annually captures global maps of the outer planets, revealed a dark spot close to the location of the bright clouds, which had been tracked from the ground. By viewing the vortex a second time, the new Hubble images confirm that OPAL really detected a long-lived feature. The new data enabled the team to create a higher-quality map of the vortex and its surroundings.

    Neptune’s dark vortices have exhibited surprising diversity over the years, in terms of size, shape, and stability (they meander in latitude, and sometimes speed up or slow down). They also come and go on much shorter timescales compared to similar anticyclones seen on Jupiter; large storms on Jupiter evolve over decades.

    Planetary astronomers hope to better understand how dark vortices originate, what controls their drifts and oscillations, how they interact with the environment, and how they eventually dissipate, according to UC Berkeley doctoral student Joshua Tollefson, who was recently awarded a prestigious NASA Earth and Space Science Fellowship to study Neptune’s atmosphere. Measuring the evolution of the new dark vortex will extend knowledge of both the dark vortices themselves, as well as the structure and dynamics of the surrounding atmosphere.

    The team, led by Wong, also included the OPAL team (Wong, Amy Simon, and Glenn Orton), UC Berkeley collaborators (Imke de Pater, Joshua Tollefson, and Katherine de Kleer), Heidi Hammel (AURA), Statia Luszcz-Cook (AMNH), Ricardo Hueso and Agustin Sánchez-Lavega (Universidad del Pais Vasco), Marc Delcroix (Société Astronomique de France), Larry Sromovsky and Patrick Fry (University of Wisconsin), and Christoph Baranec (University of Hawaii).

    See the full article here .

    Please help promote STEM in your local schools.

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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