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  • richardmitnick 2:12 pm on April 19, 2018 Permalink | Reply
    Tags: Astronomy, , , , , ,   

    From SETI Institute: “Introducing “Ultima Thule”: NASA’s Ultimate Destination in the Kuiper Belt!” 

    SETI Logo new
    SETI Institute

    March 13, 2018

    1
    Thule (here spelled “Tile”) as it appeared on a 1539 map. No image credit.

    NASA/New Horizons spacecraft

    NASA and the New Horizons team are pleased to announce that our target body in the Kuiper Belt, formally known as “(486958) 2014 MU69”, is being nicknamed Ultima Thule. The name comes from medieval mapmakers, where Thule (pronounced “thoo-lee”) was a distant and unknown island thought to be the northernmost place on Earth. “Ultima Thule” (which translates as “farthest Thule” or “beyond Thule”) has come to be used as a metaphor for any mysterious place “beyond the borders of the known world”. This is an apt metaphor for the tiny object, four billion miles away, that will be the next destination of the New Horizons spacecraft.

    The name was nominated independently by about 40 participants in the Frontier Worlds campaign, and was ranked very highly in the voting. Ultima Thule will serve as the unofficial nickname for MU69 through the flyby on New Year’s day, 2019. Later in 2019, we will work with the International Astronomical Union to establish a formal, permanent name for the body.

    Thank you to everyone who participated in the naming campaign! Now join us on our ultimate journey.

    –Mark Showalter and the New Horizons Science Team

    See the full article here .

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  • richardmitnick 1:23 pm on April 19, 2018 Permalink | Reply
    Tags: , Astronomy, , , Comet 67P/Churyumov-Gerasimenko, , ,   

    From astrobites: “A ‘Breathing’ Comet” 

    Astrobites bloc

    astrobites

    Apr 19, 2018
    Jamila Pegues

    Title: Synthesis of Molecular Oxygen via Irradiation of Ice Grains in the Protosolar Nebula
    Authors: O. Mousis, T. Ronnet, J. I. Lunine, R. Maggiolo, P. Wurz, G. Danger, and A. Bouquet
    First Author’s Institution: Aix Marseille Universite, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388, Marseille, France
    1
    Status: Accepted to The Astrophysical Journal [open access]

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    Figure 1: A picture of the comet 67P/C-G, taken by Rosetta in August 2014. The resolution is 5.3 meters/pixel. Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.

    ESA Rosetta spacecraft

    In August 2014, the Rosetta orbiter met up with the comet known as 67P/Churyumov-Gerasimenko (aka, 67P/C-G). Rosetta stuck close by, watching and observing, as the comet orbited around the Sun. Now, nearly four years later, we’re still learning new science from everything Rosetta (and its lander Philae) discovered. In today’s astrobite, we focus on one comet discovery in particular: molecular oxygen.

    See the full article here .

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    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

     
  • richardmitnick 12:46 pm on April 19, 2018 Permalink | Reply
    Tags: Astrobiologist Nathalie Cabrol, Astronomy, , , , Closest analogs of Mars that exists here on Earth, ,   

    From SETI Institute: Women in STEM -“Nathalie Cabrol – Overcoming the Odds and her Search for Life on Mars” 

    SETI Logo new
    SETI Institute

    March 23, 2018

    1
    Nathalie Cabrol

    Astrobiologist and Director of the Carl Sagan Center for Research at the SETI Institute is featured in this Sunday’s NY Times [March 25, 2018] Magazine. The profile focuses on her most recent field expedition to one of the most remote and extreme environments on Earth – the high Andes of Chile, as well as the scientific questions that drive her work. However, it also explores some of the personal and professional challenges Nathalie has faced on her journey to becoming the scientist — and woman — she is today.

    The region of Chile visited on the field expedition described in the article is one of the closest analogs of Mars that exists here on Earth. Nathalie and her team traveled there to develop and test tools and instruments that will be sent to Mars to search for possible traces of ancient microbial life.

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    Atacama Desert, Chile

    Nathalie’s research addresses questions such as: How will know what kind of life to look for on Mars and where to find it? How will we recognize what we’re looking for? And how will we understand it if we do find something?

    “Astrobiology research conducted in so-called Mars analog sites around the world, is an important part of the science we do at the SETI Institute,” said Bill Diamond, President and CEO of the SETI Institute. “Helen McDonald’s article in this past Sunday’s NY Times Magazine puts you squarely in the middle of the Atacama desert and the Altiplano of Chile – an analog site on Earth that informs us of conditions on Mars over 3 billion years ago. You can taste the salt in the dusty air and feel the crunch of crystalline gypsum giving way under foot as our NASA Astrobiology Institute (NAI) research team looks for primitive lifeforms in this vast, barren, yet spectacular landscape. The article is also a moving portrait of Dr. Nathalie Cabrol, NAI team leader and the head of research at the Carl Sagan Center here at the Institute. Reading Helen’s article, you’ll travel to early Mars, while also gaining insight into the passion and spirit of exploration that drives scientists like Nathalie.”

    Nathalie is the first woman director of the Carl Sagan Center at the SETI Institute. As such, her vision and leadership are helping to guide the shape and focus of scientific research at the SETI Institute and driving towards creative and innovative strategies to conduct – and fund – the work.

    Nathalie has been with the SETI Institute since 1998, specializes in planetary science, and is deeply involved in efforts to explore and characterize Mars. She also develops exploration strategies for the moons of the outer solar system where the conditions essential for the origin and sustenance of life are present. She is conducting research at Mars analog sites in the Andes, and in particular the adaptation strategies of life in these extreme environments. Nathalie was the spokesperson for the selection of Gusev crater as the landing site for the Spirit Rover, and is a science team member for NASA’s Mars Exploration Rover mission.

    Nathalie has published extensively in academic journals, most recently in the January issue of Astrobiology on the topic of the co-evolution of life and environment. She is the author of several books on the subjects of planetary science and terrestrial extreme environments. Nathalie is a Wings Worldquest Carey Fellow and was elected Air and Space Wings Worldquest Woman of Discovery. She is a frequent lecturer in both academic and public settings.

    See the full article here .

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  • richardmitnick 11:12 am on April 19, 2018 Permalink | Reply
    Tags: Astronomy, , , , , , GomX-4 cubesat pair   

    From European Space Agency: “ESA’s GomX-4B CubeSat relaying data across space from Danish twin” 

    ESA Space For Europe Banner

    European Space Agency

    18 April 2018

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    GomX-4B

    ESA’s latest mission has completed its in-orbit commissioning. The cereal-box-sized GomX-4B performed a transfer of data across hundreds of kilometres of space from its Danish twin.

    On 2 February, the two GomX-4 CubeSats piggybacked to space into a 500 km altitude near-polar orbit after launch on a Long March 2D rocket from Jiuquan, in China’s Gobi Desert.

    Both of the nanosatellites were built by GomSpace in Denmark. GomX-4A, financed by the Danish Ministry of Defence, is focused on monitoring and imaging Denmark’s Arctic territory. The ESA-backed GomX-4B is testing a micro-propulsion system as well as an inter-satellite radio link with its counterpart. It also carries other technology payloads, including a hyperspectral imager.

    CubeSats are small satellites based around standard 10cm cubic units, but these two ‘six-unit’ CubeSats still required weeks of in-orbit testing once they reached space, just like full-sized missions.

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    CubeSats GomX-4A and B transfer data between themselves and down to their ground station in Aalborg, Denmark, during a live press conference by manufacturer GomSpace on 12 April 2018.

    GomX-4A carries no thrusters but the agile GomX-4B used its micro-thrusters to shift its orbit relative to its twin. The satellites drifted up to 2000 km apart along their orbit, then GomX-4B performed a series of manoeuvres to reduce the separation distance back to 300 km. This allowed the pair to begin testing their radio link across various distances up to 750 km away. Later in the mission, this distance will be increased up to 4500 km for extended range tests.

    Demonstrating transfer of data between the satellites is extremely valuable. First, it increases opportunities to get images and data down to the ground from the two satellites. But it also points to future possibilities – when an inter-linked constellation of nanosatellites could cover much more territory than any single satellite, and return data to users on the ground much faster, often making it more useful.

    GomSpace showed the satellites in action for the first time during a live press conference from their Aalborg headquarters on 12 April. The retrieval process from GomX-4A to GomX-4B – and vice versa – down to Earth went according to schedule, confirming the satellite pair can share both data and images and send them home.

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    GomX-4 pair. ESA’s biggest small satellite yet: the GomX-4B six-unit CubeSat will demonstrate miniaturised technologies, preparing the way for future operational nanosatellite constellations. GomX-4B is double the size of ESA’s first technology CubeSat, GomX-3, which was released from the International Space Station in 2015. The contract with Danish CubeSat specialist GomSpace is supported through the In-Orbit Demonstration element of ESA’s General Support Technology Programme, focused on readying new products for space and the marketplace. GomX-4B will be launched and flown together with GomX-4A on 2 February 2018, designed by GomSpace for the Danish Ministry of Defence under a separate contract.
    The two CubeSats will stay linked through a new version of the software-defined radio demonstrated on GomX-3, while their separation on their shared orbit will be controlled up to a maximum 4500 km. Such intersatellite links will allow future CubeSat constellations to relay data quickly to users on the ground. The same radio system will also be used for rapid payload data downloads to Earth.

    “By having the two CubeSats operating together we’ve gained a lot of extra opportunities for in-orbit testing,” explains Roger Walker, who oversees ESA’s technology CubeSats.

    “We’re very pleased with the results of the commissioning phase, which shows that both GomX-4 CubeSats are working well, individually and together. GomX-4B’s six technology payloads are also working well. We’re now really looking forward to the next six months of the planned mission. The team will be running a series of demanding experiments with the payloads to test their performance in space.”

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    Ground antenna for CubeSats. Antenna on the roof of the GomSpace headquarters in Aalborg, Denmark, used to link and downlink data from the GomX-4 pair of CubeSats.

    GomX-4B’s HyperScout imager, manufactured by cosine Research in the Netherlands, made its own first-light image during the commissioning process.

    In addition, a miniaturised star tracker, developed by Innovative Solutions In Space in the Netherlands, also produced its first image of stars. Star trackers help spacecraft to see where they are in space, and the miniature version will undergo further testing and work with the satellite’s attitude control system to improve its pointing accuracy.

    “The GomX-4B satellite is our most advanced nanosatellite design to date,” comments Niels Buus, heading GomSpace.

    “We are pleased ESA is participating in a project which, for the first time, shows how to exploit the benefits of nanosatellite tandem formation. The platform and technology have a lot to offer to our customers and we therefore expect a lot of commercial benefit moving forward. This is definitely a next-generation nanosatellite.”

    The GomX-4B satellite and many of the payloads were funded through the ‘Fly’ element of ESA’s General Support Technology Programme dedicated to small in-orbit technology demonstration missions.

    See the full article here .

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 10:40 am on April 19, 2018 Permalink | Reply
    Tags: Astronomy, , , , Hubble 28th Anniversary Image Captures Roiling Heart of Vast Stellar Nursery,   

    From NASA/ESA Hubble Telescope: “Hubble 28th Anniversary Image Captures Roiling Heart of Vast Stellar Nursery” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    Apr 19, 2018

    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

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

    1
    Hubble celebrates 28th anniversary in style with stunning view of Lagoon Nebula.
    For 28 years, NASA’s Hubble Space Telescope has been delivering breathtaking views of the universe. Although the telescope has made more than 1.5 million observations of over 40,000 space objects, it is still uncovering stunning celestial gems.
    The latest offering is this image of the Lagoon Nebula to celebrate the telescope’s anniversary. Hubble shows this vast stellar nursery in stunning unprecedented detail.
    At the center of the photo, a monster young star 200,000 times brighter than our Sun is blasting powerful ultraviolet radiation and hurricane-like stellar winds, carving out a fantasy landscape of ridges, cavities, and mountains of gas and dust. This region epitomizes a typical, raucous stellar nursery full of birth and destruction.

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    Lagoon Nebula (Infrared-light View)

    This colorful image, taken by NASA’s Hubble Space Telescope, celebrates the Earth-orbiting observatory’s 28th anniversary of viewing the heavens, giving us a window seat to the universe’s extraordinary tapestry of stellar birth and destruction.

    At the center of the photo, a monster young star 200,000 times brighter than our Sun is blasting powerful ultraviolet radiation and hurricane-like stellar winds, carving out a fantasy landscape of ridges, cavities, and mountains of gas and dust.

    This mayhem is all happening at the heart of the Lagoon Nebula, a vast stellar nursery located 4,000 light-years away and visible in binoculars simply as a smudge of light with a bright core.

    The giant star, called Herschel 36, is bursting out of its natal cocoon of material, unleashing blistering radiation and torrential stellar winds (streams of subatomic particles) that push dust away in curtain-like sheets. This action resembles the Sun bursting through the clouds at the end of an afternoon thunderstorm that showers sheets of rainfall.

    Herschel 36’s violent activity has blasted holes in the bubble-shaped cloud, allowing astronomers to study this action-packed stellar breeding ground.

    The hefty star is 32 times more massive and 40,000 times hotter than our Sun. It is nearly nine times our Sun’s diameter. Herschel 36 is still very active because it is young by a star’s standards, only 1 million years old. Based on its mass, it will live for another 5 million years. In comparison, our smaller Sun is 5 billion years old and will live another 5 billion years.

    This region epitomizes a typical, raucous stellar nursery full of birth and destruction. The clouds may look majestic and peaceful, but they are in a constant state of flux from the star’s torrent of searing radiation and high-speed particles from stellar winds. As the monster star throws off its natal cocoon of material with its powerful energy, it is suppressing star formation around it.

    However, at the dark edges of this dynamic bubble-shaped ecosystem, stars are forming within dense clouds of gas and dust. Dark, elephant-like “trunks” of material represent dense pieces of the cocoon that are resistant to erosion by the searing ultraviolet light and serve as incubators for fledgling stars. They are analogous to desert buttes that resist weather erosion.

    The Hubble view shows off the bubble’s 3D structure. Dust pushed away from the star reveals the glowing oxygen gas (in blue) behind the blown-out cavity. Herschel 36’s brilliant light is illuminating the top of the cavity (in yellow). The reddish hue that dominates part of the region is glowing nitrogen. The dark purple areas represent a mixture of hydrogen, oxygen, and nitrogen.

    The image shows a region of the nebula measuring about 4 light-years across.

    The observations were taken by Hubble’s Wide Field Camera 3 between Feb. 12 and Feb. 18, 2018.

    HUBBLE TRIVIA 2018

    Launched on April 24, 1990, NASA’s Hubble Space Telescope has made more than 1.5 million observations of more than 43,500 celestial objects.
    In its 28-year lifetime the telescope has made more than 163,500 trips around our planet. Hubble has racked up plenty of frequent-flier miles, about 4 billion miles.
    Hubble observations have produced more than 153 terabytes of data, which are available for present and future generations of researchers.
    Astronomers using Hubble data have published more than 15,500 scientific papers.

    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 10:19 am on April 19, 2018 Permalink | Reply
    Tags: Astronomy, , Australian Astronomical Observatory, , , Finding our Sun’s lost siblings, HERMES spectrograph on the AAT,   

    From University of New South Wales: “Finding our Sun’s lost siblings” 

    U NSW bloc

    University of New South Wales

    18 Apr 2018
    No writer credit

    In a huge galactic archaeology project, astronomers have revealed the “DNA” of more than 340,000 stars in the Milky Way, which should help them find the siblings of the Sun, now scattered across the sky.

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    Our galaxy, the Milky Way. Image: Shutterstock

    An Australian-led group of astronomers working with European collaborators has revealed the “DNA”, or spectra, of more than 340,000 stars in the Milky Way, which should help them find the siblings of the Sun, now scattered across the sky.

    UNSW scientist Dr Sarah Martell leads the survey observations for the ambitious galactic archaeology project called GALAH, which was launched in late 2013 as part of a quest to uncover the formulation and evolution of galaxies.

    When complete, GALAH will have investigated more than a million stars, and today makes its first major public release of data. The GALAH survey used the HERMES spectrograph at the Australian Astronomical Observatory’s (AAO) 3.9-metre Anglo-Australian Telescope near Coonabarabran in NSW to collect spectra for the 340,000 stars.

    AAO HERMES spectrograph on the Anglo-Australian Telescope


    AAO Anglo Australian Telescope near Siding Spring, New South Wales, Australia, Altitude 1,100 m (3,600 ft)

    The information gathered traces the ancestry of stars, showing astronomers how the Universe went from having only hydrogen and helium just after the Big Bang to being filled with all the elements present now on Earth that are necessary for life.

    Dr Martell, from the UNSW School of Physics, says the Sun, like all stars, was born in a group or cluster of thousands of stars.

    “Every star in that cluster will have the same chemical composition, or DNA. These clusters are quickly pulled apart by our Milky Way Galaxy and are now scattered across the sky,” she says.

    “The GALAH team’s aim is to make DNA matches between stars to find their long-lost sisters and brothers.”

    Dr Gayandhi De Silva, of the University of Sydney and AAO – the HERMES instrument scientist who oversaw the groups working on today’s major data release – says: “No other survey has been able to measure as many elements for as many stars as GALAH.

    “This data will enable such discoveries as the original star clusters of the Galaxy, including the Sun’s birth cluster and solar siblings. There is no other dataset like this ever collected anywhere else in the world,” Dr De Silva says.

    For each star, the DNA represents the amount they contain of each of nearly two dozen chemical elements such as oxygen, aluminium, and iron.

    Astronomers, of course, cannot simply collect the DNA of stars with mouth swabs, but instead collect starlight, using a technique called spectroscopy.

    The light from the star is collected by the telescope and then passed through an instrument called a spectrograph, which splits the light into detailed rainbows, or spectra.

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    A schematic of the HERMES instrument showing how star light from the telescope AAT is split into four different channels. Credit: The Australian Astronomical Observatory.

    Associate Professor Daniel Zucker, from Macquarie University and the AAO, says astronomers measure the locations and sizes of dark lines in the spectra to work out the amount of each element in a star.

    “Each chemical element leaves a unique pattern of dark bands at specific wavelengths in these spectra, like fingerprints,” he says.

    Dr Jeffrey Simpson of the AAO says it takes about an hour to collect enough photons of light for each star: “Thankfully, we can observe 360 stars at the same time using fibre optics,” he says.

    The GALAH team has spent more than 280 nights at the telescope since 2014 to collect all the data.

    The GALAH survey is the brainchild of Professor Joss Bland-Hawthorn from the University of Sydney and the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) and Professor Ken Freeman of the Australian National University (ANU).

    It was conceived more than a decade ago as a way to unravel the history of our Milky Way galaxy. The HERMES instrument was designed and built by the AAO specifically for the GALAH survey. Measuring the abundance of each chemical in so many stars is an enormous challenge. To do this, GALAH has developed sophisticated analysis techniques.

    PhD student Sven Buder of the Max Planck Institute for Astronomy, Germany, who is lead author of the scientific article describing the GALAH data release, is part of the analysis effort of the project, working with PhD student Ly Duong and Professor Martin Asplund of ANU and ASTRO 3D.

    Mr Buder says: “We train [our computer code] The Cannon to recognise patterns in the spectra of a subset of stars that we have analysed very carefully, and then use The Cannon’s machine learning algorithms to determine the amount of each element for all of the 340,000 stars.“

    Ms Duong says: “The Cannon is named for Annie Jump Cannon, a pioneering American astronomer who classified the spectra of around 340,000 stars by eye over several decades a century ago. Our code analyses that many stars in far greater detail in less than a day.”

    The GALAH survey’s data release is timed to coincide with the huge release of data on 25 April from the European Gaia satellite, which has mapped more than 1.6 billion stars in the Milky Way, making it by far the biggest and most accurate atlas of the night sky to date.

    In combination with velocities from GALAH, Gaia data will give not just the positions and distances of the stars, but also their motions within the Galaxy.

    Professor Tomaz Zwitter of the University of Ljubljana in Slovenia says today’s results from the GALAH survey will be crucial for interpreting the results from Gaia: “The accuracy of the velocities that we are achieving with GALAH is unprecedented for such a large survey,” he says.

    Dr Sanjib Sharma from the University of Sydney says: “For the first time we’ll be able to get a detailed understanding of the history of the Galaxy.”

    See the full article here .

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    U NSW Campus

    Welcome to UNSW Australia (The University of New South Wales), one of Australia’s leading research and teaching universities. At UNSW, we take pride in the broad range and high quality of our teaching programs. Our teaching gains strength and currency from our research activities, strong industry links and our international nature; UNSW has a strong regional and global engagement.

    In developing new ideas and promoting lasting knowledge we are creating an academic environment where outstanding students and scholars from around the world can be inspired to excel in their programs of study and research. Partnerships with both local and global communities allow UNSW to share knowledge, debate and research outcomes. UNSW’s public events include concert performances, open days and public forums on issues such as the environment, healthcare and global politics. We encourage you to explore the UNSW website so you can find out more about what we do.

     
  • richardmitnick 9:42 am on April 19, 2018 Permalink | Reply
    Tags: Astronomy, , , , ,   

    From University of New South Wales: “NASA’s new satellite a boost for UNSW starquake research” 

    U NSW bloc

    University of New South Wales

    19 Apr 2018
    Deborah Smith

    The successful launch of NASA’s planet-hunting satellite TESS will allow UNSW scientists to study the properties of nearby stars from their internal ringing sounds.

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    NASA’s Transiting Exoplanet Survey Satellite,TESS, will search for planets beyond our solar system. Image: NASA.

    The successful launch today of NASA’s planet-hunting satellite will allow UNSW scientists to study the properties of nearby stars from their internal ringing sounds.

    Associate Professor Dennis Stello, from the School of Physics, had a front row seat at Cape Canaveral in Florida when the SpaceX Falcon 9 rocket carrying NASA’s Transiting Exoplanet Survey Satellite, TESS, blasted off this morning at 8.51am Australian Eastern Standard Time.

    In a first-of-its-kind mission, TESS will spend about two years surveying 200,000 of the brightest stars to search for planets beyond our solar system. It will identify planets ranging from rocky Earth-sized worlds to gas giants, orbiting a wide range of stellar types and orbital distances.

    “The launch went very smoothly,” says Stello, who is part of the TESS Asteroseismic Science Consortium. “This is a very exciting time for us. TESS will be providing data on stars and planets in our cosmic backyard for many years to come.”

    TESS will be watching for phenomena called transits. A transit occurs when a planet passes in front of its star from the observer’s perspective, causing a periodic and regular dip in the star’s brightness. More than 78 percent of the approximately 3,700 confirmed exoplanets have been found using transits.

    TESS is a follow-up to the Kepler spacecraft, one of NASA’s most successful missions which found more than 2,600 exoplanets, most orbiting faint stars between 300 and 3,000 light-years from Earth using the transit method.

    TESS will focus on closer stars, between 30 and 300 light-years away, and 30 to 100 times brighter than Kepler’s targets.

    “The measurements made by TESS also allow us to detect brightness variations caused by ringing sounds inside the stars from starquakes that make the stars vibrate,” says Stello.

    By analysing the frequencies of the ringing, Stello and his team can infer the properties of the stars, such as their size, mass, and age.

    “This method, called asteroseismology, helps us understand newly discovered planet systems, and gives us a way to study detailed physics inside stars under extreme conditions we cannot reproduce here on Earth,” he says.

    See the full article here .

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    U NSW Campus

    Welcome to UNSW Australia (The University of New South Wales), one of Australia’s leading research and teaching universities. At UNSW, we take pride in the broad range and high quality of our teaching programs. Our teaching gains strength and currency from our research activities, strong industry links and our international nature; UNSW has a strong regional and global engagement.

    In developing new ideas and promoting lasting knowledge we are creating an academic environment where outstanding students and scholars from around the world can be inspired to excel in their programs of study and research. Partnerships with both local and global communities allow UNSW to share knowledge, debate and research outcomes. UNSW’s public events include concert performances, open days and public forums on issues such as the environment, healthcare and global politics. We encourage you to explore the UNSW website so you can find out more about what we do.

     
  • richardmitnick 9:28 am on April 19, 2018 Permalink | Reply
    Tags: Astronomy, , , , ,   

    From Kavli MIT Institute of Astrophysics and Space Research: “To Seek Out New Life: How the TESS Mission Will Accelerate the Hunt for Livable Alien Worlds’ 

    KavliFoundation

    http://www.kavlifoundation.org/institutes

    Kavli MIT Institute of Astrophysics and Space Research

    Kavli MIT Institute For Astrophysics and Space Research

    The just-launched Transiting Exoplanet Survey Satellite (TESS) could soon provide the breakthrough identification of dozens of potentially habitable exoplanets
    right in our cosmic backyard.

    NASA/TESS

    A NEW ERA IN THE SEARCH FOR EXOPLANETS—and the alien life they might host—has begun. Aboard a SpaceX rocket, the Transiting Exoplanet Survey Satellite (TESS) launched on April 18, 2018, at 6:51 PM EDT. The TESS mission, developed with support from The Kavli Foundation, is led by the Massachusetts Institute of Technology (MIT) and the MIT Kavli Institute for Astrophysics and Space Research.

    Over the next two years, TESS will scan the 200,000 or so nearest and brightest stars to Earth for telltale dimming caused when exoplanets cross their stars’ faces. Among the thousands of new worlds TESS is expected to discover should be hundreds ranging in size from about one to two times Earth. These small, mostly rocky planets will serve as prime targets for detailed follow-up observations by other telescopes in space and on the ground.

    The goal for those telescopes will be to characterize the newfound exoplanets’ atmospheres. The particular mixtures of gases in an atmosphere will reveal key clues about a world’s climate, history, and if it might even be hospitable to life.

    The Kavli Foundation spoke with two scientists on the TESS mission to get an inside look at its development and revolutionary science aim of finding the first “Earth twin” in the universe.

    The participants were:

    GREG BERTHIAUME – is the Instrument Manager for the TESS mission, in charge of ensuring the spacecraft’s cameras and other equipment will perform their science tasks. Berthiaume is based at the Massachusetts Institute of Technology’s (MIT) Lincoln Laboratory and he is also a member of the MIT Kavli Institute for Astrophysics and Space Research.

    DIANA DRAGOMIR – is an observational astronomer whose focus is on small exoplanets. Dragomir is a Hubble Postdoctoral Fellow at the MIT Kavli Institute for Astrophysics and Space Research.

    THE KAVLI FOUNDATION: Starting with the big picture, why is TESS important?

    DIANA DRAGOMIR: TESS is going to find thousands of exoplanets, which might not sound like a big deal, because we already know of nearly 4,000. But most of those discovered planets are too far away for us to do anything more than just know their size and that they are there. The difference is that TESS will be looking for planets around stars very close to us. When stars are closer to us, they’re also brighter from our point of view, and that helps us discover and study the planets around them much more easily.

    GREG BERTHIAUME: One of the things TESS is doing is helping to answer the fundamental question, “Is there other life in the universe?” People have been wondering that for thousands of years. Now TESS won’t answer that question directly, but it’s a step, just like Diana mentioned, on the path to getting us the data to see where there might be other life out there. That’s something we’ve been struggling with and questioning since we were able to come up with questions.

    TKF: What exactly do you expect TESS to find?

    DRAGOMIR: TESS will probably find 100 to 200 approximately Earth-size worlds, as well as thousands of more exoplanets all the way up to Jupiter in size.

    BERTHIAUME: We’re trying to find planets that are Earth analogs, meaning they’ll be Earth-like in their characteristics, such as size, mass, and so on. That means we want to find planets with atmospheres, with gravity similar to Earth’s. We want to find planets that are cool enough so water can be liquid on their surfaces, and not so cold that the water is frozen all the time. We call these “Goldilocks” planets, located in a star’s “habitable zone.” That’s really our target.

    DRAGOMIR: Exactly right. We want to find the first “Earth twin.” TESS will mainly find planets in the habitable zone of red dwarfs. These are stars a bit smaller and cooler than the Sun. A planet around a red dwarf can be located in an orbit closer to its star than it could be with a hotter star like our Sun and still maintain that nice, Goldilocks temperature. Closer orbits translate to more transits, or star crossings, which makes these red dwarf planets easier to find and study than planets around Sun-like stars.

    Astronomers are working hard on ways that we might push the TESS data and find some planets in the habitable zone of Sun-like stars, too. It’s challenging because those planets have longer orbital periods—years, that is—than close-in planets. That means we need a lot more observation time in order to detect enough transits of the planets across their stars to say we’ve definitely detected a planet. But we’re hopeful, so stay tuned!

    TKF: What do you need to see in order to deem any of the planets discovered by TESS as potentially habitable?

    DRAGOMIR: We want a planet to be close to Earth in size for all the reasons we just gave, but there’s a small problem with that. Those sorts of planets will probably have pretty small atmospheres, compared to how much rock makes up their bulk. And for most telescopes to be able to look at an atmosphere in detail, we actually need the planet to have a substantial atmosphere.

    This is because of a technique we use called transmission spectroscopy. It gathers the light from the star that has gone through the atmosphere of the planet when the planet is crossing the star. That light comes to us with a spectrum of the planet’s atmosphere imprinted on it, which we can analyze to identify the composition of the atmosphere. The more atmosphere there is, the more material there is that can imprint on the spectrum, giving us a bigger signal.

    If the light from the star is going through very little atmosphere, though, like we’d be looking at with an Earth twin, the signal would be very small. Based on what TESS finds, we’re therefore going to be starting with bigger planets that have a lot of atmosphere, and as we get better instruments, we’re going to move towards smaller and smaller planets with less atmosphere. It’s those latter planets which will more likely be habitable.

    BERTHIAUME: What we’re going to look for in the atmosphere are things like water vapor, oxygen, carbon dioxide—the standard gases we see in our atmosphere that life needs and life produces. We’re also going to try and measure the nasty things that aren’t compatible with life as we know it on Earth. For instance, it would be a bad thing for biology if there were too much ammonia in a world’s atmosphere. Hydrocarbons, like methane, would also be problematic in too high an abundance.

    TKF: Diana, your specialty is exoplanets smaller than Neptune—a planet four times bigger than Earth. What is our general knowledge about those kinds of worlds and how will TESS help with your research?

    DRAGOMIR: One thing we know about these planets is that they are extremely common compared to planets larger than Neptune. So that’s good. We therefore expect TESS to find lots and lots of planets smaller than Neptune for us to look at.

    Although small is bad for getting those atmospheric imprints we just talked about, if the stars are nearby and bright, we might still be able to get enough light for doing good studies. I’m hoping that we’ll get enough below Neptune-size that we’ll start looking at the atmospheres of “super-Earths,” which are planets twice the size of Earth or so. We don’t have any super-Earths in our solar system, so we’d love to get a closer look at one of these kinds of worlds. And just maybe, if we find a really, really good planetary candidate, we may be able to start looking at the atmosphere of an Earth-sized planet.

    With my research, one more thing TESS could really help with is figuring out the boundary between a very gassy planet like Neptune and a very rocky planet like Earth. We believe it’s mostly a matter of mass; have too much mass, and the planet stars to hold into a thick atmosphere. Right now, we’re not sure where that threshold is. And that matters so we know when a planet is rocky and potentially habitable, or gassy and not habitable.

    TKF: Greg, as the TESS Instrument Manager, a lot rides on your shoulders for the mission’s success. Can you tell us a bit about your job?

    BERTHIAUME: My job as instrument manager is different from a science job, for sure. My job was to make sure that all of the pieces, all the parts that go into the four flight cameras and the image processing hardware all play and work together and give us the great data that we need for Diana to go and continue to explore exoplanets. My personal role on the mission actually ends shortly after launch. Once we’ve demonstrated that the satellite provides the data that we expect, and we deal with any surprises that may come up, then I move on and data goes off to the science community.

    I definitely feel responsible for getting the quality of the data as high as it possibly can be. A lot of people worked really hard for years to build the cameras that are flying on TESS and it’s been great to be part of that team.

    TKF: New exoplanet missions like the European Space Agency’s Ariel and Plato satellites are slated to begin in the late 2020s. How might these future spacecraft complement and build on TESS’ body of work?

    DRAGOMIR: The great thing about TESS is that it’s going to give us a lot to choose from in terms of the best options for planets we’ll want to study. In that way, TESS will set the stage for Ariel’s mission, which is to deeply study the atmospheres of a select group of exoplanets.

    The Plato mission will be looking for planets that are habitable, but around bigger stars like the Sun, whereas TESS will focus on looking for habitable planets around smaller stars. I’m happy with that because I don’t want us to put all of our eggs in one basket by only looking at red dwarf stars with TESS. Planets around these red dwarfs are very exciting right now because they’re easier to study and they transit their stars more often, making them easier to find. But at the same time, red dwarfs tend to be much more active than the Sun. When a star is active, that means it often expels bursts of radiation called flares. These flares could be very damaging to a planet’s atmosphere and make the world uninhabitable.

    In the end, we of course live around a Sun-like star, and so far, we are the only “we” we know of in the universe. So for those reasons, it’s great to have Plato complementarily come along and find those planets around suns that TESS will probably not be able to find.

    TKF: When do you expect TESS’ first discoveries of brand new worlds to be reported?

    BERTHIAUME: First, it’s going to take a while to get TESS into its unique orbit. It’s the first time we’re putting a spacecraft in a new kind of far-ranging, highly elliptical orbit, where the gravity from the Earth and the Moon will keep TESS very stable, both from an orbit perspective and from a thermal perspective. So a big part of what’s going to happen over the first six weeks is just achieving that final orbit.

    Then there’s a period of time where there’ll be data collected to make sure the instruments are working as expected, as well as getting our data processing pipeline tuned up. I think we’ll start to see interesting results come out sometime this summer.

    TKF: Besides new worlds, what else might TESS reveal about the universe?

    2
    A set of flight camera electronics on one of the TESS cameras, developed by the MIT Kavli Institute for Astrophysics and Space Research (MKI). (Image: MIT Kavli Institute)

    DRAGOMIR: Because TESS is observing so much of the sky, it’s going to see lots of things that are happening in real-time, not just exoplanets crossing stars. As for those stars, we can learn a lot about their properties and even measure their masses quite precisely by doing asteroseismology with TESS. This technique involves tracking brightness changes as sound waves move through the interiors of stars—just like how seismic waves pass through the Earth’s rock and molten insides during earthquakes.

    We’ll also be studying the flaring activity of the stars, which as we spoke about earlier might make close-in, temperate planets around red dwarf stars uninhabitable.

    Moving up in size, scientists will want to search the TESS data for evidence of small black holes. These extreme objects, formed when colossal stars explode, can orbit normal stars that are still “alive,” so to speak. These systems will help us better understand how those black holes form and how they interact with companion stars.

    And then finally, going even bigger, TESS will look at galaxies called quasars. These ultra-bright galaxies are powered by supermassive black holes in their cores. TESS will help us monitor how quasars’ brightness changes, which we can link back to the dynamics of their black holes.

    TKF: The James Webb Space Telescope, hailed as the successor to the Hubble Space Telescope, has long been talked about as a primary instrument for doing the detailed follow-up observations on promising exoplanets found by TESS. However, James Webb’s launch, already delayed multiple times, just got pushed out yet another year, to 2020. How will the ongoing James Webb delays affect the TESS mission?

    DRAGOMIR: The James Webb delay is not so much of a problem because it actually gives us more time to collect great target planets with TESS. Before we can use James Webb to really observe candidate exoplanets and study their atmospheres, we first need to confirm the planets are real—that what we think are planets are not false positives caused, for instance, by stellar activity. That confirmation process takes weeks, using support observations from ground-based telescopes. It will then also take weeks to months to obtain the mass of the planets. We measure that by registering how much planets cause their host stars to experience slight “wobbles” in their motion over time, owing to the planets’ gravities, which are determined by their mass.

    Once you have that mass, plus the size of an exoplanet based on how much starlight it blocks during a TESS detection, you can measure its density and determine if it’s rocky or gaseous. With this information, it is then easier to decide which planets we want to prioritize, and the more we can make sense out of what James Webb will tell us about their atmospheres.

    TKF: Spacecraft sometimes have humorous or even profound extra elements built into them. One example: the “Golden Records” on the twin Voyager spacecraft, which contain images and sounds of life and civilization on Earth, including the Taj Mahal and birdsong. Are there any such items included on TESS? Any subtle maker’s marks or messages?

    BERTHIAUME: One of the things that’s flying along with TESS is a metal plaque that has the signatures of many of the people who worked on developing and building the spacecraft. That was an exciting thing for us.

    DRAGOMIR: That’s cool. I didn’t know that!

    BERTHIAUME: Also, NASA ran an international contest inviting people from around the world to submit drawings of what they thought exoplanets might look like. I know many children participated. All of those drawings were scanned onto a thumb drive and they’re flying along with TESS. The spacecraft’s orbit is stable for a century at least, so the plaque and the drawings will be in space for a long time!

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    The Kavli Foundation, based in Oxnard, California, is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work.

    The Foundation’s mission is implemented through an international program of research institutes, professorships, and symposia in the fields of astrophysics, nanoscience, neuroscience, and theoretical physics as well as prizes in the fields of astrophysics, nanoscience, and neuroscience.

    Mission Statement

    The mission of the MIT Kavli Institute (MKI) for Astrophysics and Space Research is to facilitate and carry out the research programs of faculty and research staff whose interests lie in the broadly defined area of astrophysics and space research. Specifically, the MKI will

    Provide an intellectual home for faculty, research staff, and students engaged in space- and ground-based astrophysics
    Develop and operate space- and ground-based instrumentation for astrophysics
    Engage in technology development
    Maintain an engineering and technical core capability for enabling and supporting innovative research
    Communicate to students, educators, and the public an understanding of and an appreciation for the goals, techniques and results of MKI’s research.

     
  • richardmitnick 8:53 am on April 19, 2018 Permalink | Reply
    Tags: Astronomy, , , , , ,   

    From ESA: “Where is the Universe’s missing matter?” 

    ESA Space For Europe Banner

    European Space Agency

    18 April 2018

    Jiangtao Li
    University of Michigan, USA
    Email: jiangtal@umich.edu
    Tel: 734-383-2089

    Joel Bregman
    University of Michigan, USA
    Email: jbregman@umich.edu
    Tel: 734-764-2667

    Norbert Schartel
    XMM-Newton Project Scientist
    European Space Agency
    Email: norbert.schartel@esa.int

    1
    Searching galactic haloes for ‘missing’ matter. No image credit.

    ESA/XMM Newton

    Astronomers using ESA’s XMM-Newton space observatory have probed the gas-filled haloes around galaxies in a quest to find ‘missing’ matter thought to reside there, but have come up empty-handed – so where is it?

    All the matter in the Universe exists in the form of ‘normal’ matter or the notoriously elusive and invisible dark matter, with the latter around six times more prolific.

    Curiously, scientists studying nearby galaxies in recent years have found them to contain three times less normal matter than expected, with our own Milky Way Galaxy containing less than half the expected amount.

    Caterpillar Project A Milky-Way-size dark-matter halo and its subhalos circled, an enormous suite of simulations . Griffen et al. 2016

    “This has long been a mystery, and scientists have spent a lot of effort searching for this missing matter,” says Jiangtao Li of the University of Michigan, USA, and lead author of a new paper http://iopscience.iop.org/article/10.3847/2041-8213/aab2af/meta .

    “Why is it not in galaxies — or is it there, but we are just not seeing it? If it’s not there, where is it? It is important we solve this puzzle, as it is one of the most uncertain parts of our models of both the early Universe and of how galaxies form.”

    Rather than lying within the main bulk of the galaxy, the part can be observed optically, researchers thought it may instead lie within a region of hot gas that stretches further out into space to form a galaxy’s halo. These hot, spherical haloes have been detected before, but the region is so faint that it is difficult to observe in detail – its X-ray emission can become lost and indistinguishable from background radiation. Often, scientists observe a small distance into this region and extrapolate their findings but this can result in unclear and varying results.

    Jiangtao and colleagues wanted to measure the hot gas out to larger distances using ESA’s XMM-Newton X-ray space observatory. They looked at six similar spiral galaxies and combined the data to create one galaxy with their average properties.

    “By doing this, the galaxy’s signal becomes stronger and the X-ray background becomes better behaved,” adds co-author Joel Bregman, also of the University of Michigan.

    “We were then able to see the X-ray emission to about three times further out than if observing a single galaxy, which made our extrapolation more accurate and reliable.”

    Massive and isolated spiral galaxies offer the best chance to search for missing matter. They are massive enough to heat gas to temperatures of millions of degrees so that they emit X-rays, and have largely avoided being contaminated by other material through star formation or interactions with other galaxies.

    Still missing

    The team’s results showed that the halo surrounding galaxies like the ones observed cannot contain all of the missing matter after all. Despite extrapolating out to almost 30 times the radius of the Milky Way, nearly three-quarters of the expected material was still missing.

    Milky Way Dark Matter Halo Credit ESO L. Calçada

    There are two main alternative theories as to where it could be: either it is stored in another gas phase that is poorly observed – perhaps either a hotter and more tenuous phase or a cooler and denser one – or within a patch of space that is not covered by our current observations or emits X-rays too faintly to be detected.

    Either way, since the galaxies do not contain enough missing matter they may have ejected it out into space, perhaps driven by injections of energy from exploding stars or by supermassive black holes.

    “This work is important to help create more realistic galaxy models, and in turn help us better understand how our own Galaxy formed and evolved,” says Norbert Schartel, ESA XMM-Newton project scientist. “This kind of finding is simply not possible without the incredible sensitivity of XMM-Newton.”

    “In the future, scientists can add even more galaxies to our study samples and use XMM-Newton in collaboration with other high-energy observatories, such as ESA’s upcoming Advanced Telescope for High-ENergy Astrophysics, Athena, to probe the extended, low-density parts of a galaxy’s outer edges, as we continue to unravel the mystery of the Universe’s missing matter.”

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 10:20 am on April 18, 2018 Permalink | Reply
    Tags: Astronomy, , , , , , Turning Pixels Into Planets   

    From Ethan Siegel- “NASA Kepler’s Scientists Are Doing What Seems Impossible: Turning Pixels Into Planets” 

    From Ethan Siegel

    Apr 18, 2018

    1
    This highly pixelated view of TRAPPIST-1 shows the amount of light detected by each pixel in a small section of Kepler’s onboard camera. The light collected from TRAPPIST-1 is visible at the center of the image. Not directly visible are the planets that orbit TRAPPIST-1. NASA Ames/W. Stenzel.

    When you think of what’s out there in the vast recesses of space, glorious images of galaxies, stars, and new worlds probably leap to mind. A combination of the greatest images from Hubble and some gorgeous artistic renderings are how we visualize the Universe, but that’s not what most telescopes or observatories see, and that’s certainly not where most of the science gets done. NASA’s Kepler mission, famous for discovering thousands of planets outside of our Solar System, never actually images a planet.

    NASA/Kepler Telescope

    Instead, they simply image an unresolved star, or more accurately, around 100,000 stars at once. After doing that for weeks, months, or years, they announce the discovery of candidate planets, including properties like their radius and orbital period. A raw image shows nothing but pixels of a saturated star, but it’s what you do with the data that counts. Here’s the science of how a few pixels become an entire solar system.

    2
    This artist’s impression displays TRAPPIST-1 and its planets reflected in a surface. The potential for water on each of the worlds is also represented by the frost, water pools, and steam surrounding the scene. However, it is unknown whether any of these worlds actually still possess atmospheres, or if they’ve been blown away by their parent star. NASA/R. Hurt/T. Pyle.

    TRAPPIST-1 is perhaps the most exciting of the recent discoveries made with the Kepler spacecraft. Although it’s a small, low-mass star that’s red and dim, we’ve discovered an incredibly prolific solar system: 7 planets, all of which are approximately Earth-sized, including three that might have the right temperatures and conditions for liquid water on their surface. Best of all, it’s only 40 light years away, meaning that on a galactic scale, it’s right in our own backyard. But when you look at it through NASA’s Kepler telescope, which is where the best data on this planetary system comes from, this is what you see.

    3
    The viewing area of the Kepler satellite’s K2 Campaign 12, which includes TRAPPIST-1 in the region indicated above. NASA Ames/W. Stenzel.

    You don’t see planets, you don’t see orbits, you don’t even see anything that tells you about the properties of the star or its solar system. All you see is a set of pixels, indicating you have a light source of some type. There are other light sources nearby — space is a busy place — and Kepler is imaging all of them at once, continuously. Those two facts:

    that Kepler is imaging thousands upon thousands of stars at once,
    and that it’s imaging all of these stars continuously, over long periods of time,

    is what enables us to do the incredible science we’re doing. Take a look at this animation of the raw data over an interestingly long period of time.

    3
    When you apply a mask to TRAPPIST-1, as viewed by Kepler, and take a look at how the light evolves over time, a huge amount of information can be gleaned from a seemingly noisy few pixels. NASA / Kepler / K2 Campaign 12 team / Geert Barentsen.

    You’ll notice that the brightness of the star appears to change with time. But you’ll also notice, if you’re careful, that the background brightness of everything else — both other objects and the background “noise” of space itself — changes with time, too. If you’re looking at the raw data itself, there are things you need to know about it before you attempt to make any use of it. There are no corrections for smearing of data across multiple pixels in the raw data. There are no bias subtractions included in the raw data. The field (where there are no stars) isn’t flat, and so this introduces noise into the raw data. There are no flags for the time where the data is of poor quality, such as when the spacecraft’s thrusters fire. And there is no flagging of cosmic rays, which can influence the spacecraft’s software.

    Still, when you take all of this into account, the raw data itself (individual red points, below) still shows some remarkable features that are worth looking at.

    4
    A quick-look lightcurve of the long cadence data for TRAPPIST-1, derived from the raw data itself, reveals sinusoidal patterns due to star spots and at least 6 planets. NASA / Kepler / K2 Campaign 12 team / Geert Barentsen.

    There are sinusoidal (periodioc up-and-down) patterns, which tell you there are sunspots on the main star: some portions of the star are fainter than average. Also, there are a few big dips in the total amount of light in the long-cadence data, where between 0.5% and 1% of the light is temporarily blocked/dimmed over the course of approximately 30 minutes. When you normalize the data and make all the corrections that the raw data doesn’t possess, and then add in follow-up data from other telescopes and observatories, you can clearly see the periodic nature of the planets. When a world transits, or passes in front of the star, it blocks a portion of the light, making the star appear dimmer. Over time, these dips appear periodically, teaching us about the orbits of these worlds.

    5
    This diagram shows the changing brightness of the ultra cool dwarf star TRAPPIST-1 over a period of 20 days in September and October 2016 as measured by NASA’s Spitzer Space Telescope and many other telescopes on the ground. On many occasions the brightness of the star drops for a short period and then returns to normal. These events, called transits, are due to one or more of the star’s seven planets passing in front of the star and blocking some of its light. The lower part of the diagram shows which of the system’s planets are responsible for the transits. ESO/M. Gillon et al.

    This gives us all the information we need to deduce many of the properties of these worlds.

    Because we know the size and brightness of the star, we can deduce the radius of each transiting world.
    Because we know the mass of the star and how orbits work, we can figure out the distance of each planet from the star.
    Because we know the temperature of the star, we can figure out which worlds would have the right conditions for liquid water if they had Earth-like atmospheres.
    And because these worlds mutually tug on each other, inducing subtle shifts in one another’s orbits, we can infer what their masses ought to be.

    When you put all of this together, here’s how these worlds look, compared to the inner, rocky worlds of our own Solar System.

    6
    When all the information obtained from Kepler, Spitzer, and ground-based telescopes that have observed the TRAPPIST-1 are compiled, we can deduce the masses, radii, and orbital parameters of each of the discovered worlds. They are not so different from the four rocky worlds in our own solar system. We’re dying to know more. No image credit.

    NASA/Spitzer Infrared Telescope

    If you’re looking for the most Earth-like world among them all, your best bet is the fourth rock from the star: TRAPPIST-1e. Sure, it’s much closer to its star at just a distance of 3% our distance from the Sun and with an orbital period of 6 days, but its star is much smaller, dimmer and cooler. It’s only 9% smaller than Earth and, within the errors, the same density as our world. You’d weigh 93% of what you’d weigh on Earth on TRAPPIST-1e, as its gravity is almost identical to our own. Most impressively, it has properties consistent with being a dense, rocky world with a thin atmosphere encircling it. Of all the worlds we’ve found orbiting stars beyond the Sun, TRAPPIST-1e, may yet be the most Earth-like of all.

    7
    The various planets orbiting around TRAPPIST-1, seven of which have been found so far, all have unique properties that we can infer from their sizes, masses, and orbital parameters. The fourth planet from this star, TRAPPIST-1e, may be the most Earth-like of all. NASA / JPL-Caltech.

    Despite being around a red dwarf and likely locked to its star, the exoplanets orbiting TRAPPIST-1 are incredibly promising for life-giving conditions. They range from roasting to temperate to frozen with sub-surface oceans to potentially light and fluffy, with outer gas envelopes. All of this information — about the worlds around this star, their sizes, their orbits, and even their masses — can all be derived from those tiny, saturated pixels of light that Kepler picked up. And it isn’t just this one system; every star that experiences transits that have been observed by Kepler shows this.

    8
    A visualization of the planets found in orbit around other stars in a specific patch of sky probed by the NASA Kepler mission. As far as we can tell, practically all stars have planetary systems around them.
    ESO / M. Kornmesser.

    It isn’t the image itself that gives you this information, but rather how the light from image changes over time, both relative to all the other stars and relative to itself. The other stars out there in our galaxy have sunspots, planets, and rich solar systems all their own. As Kepler heads towards its final retirement and prepares to be replaced by TESS, take a moment to reflect on just how it’s revolutionized our view of the Universe. Never before has such a small amount of information taught us so much.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
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