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  • richardmitnick 2:08 pm on October 28, 2019 Permalink | Reply
    Tags: "Life on the Red Edge", , , , , , Exoplanet research   

    From AAS NOVA: “Life on the Red Edge” 

    AASNOVA

    From AAS NOVA

    28 October 2019
    Tarini Konchady

    1
    An artist’s illustration of the Kepler-186 system, highlighting the planet Kepler-186f. Kepler-186f is an Earth-sized planet orbiting in the habitable zone of its star. [NASA Ames/SETI Institute/JPL-Caltech/T. Pyle]

    How can we identify life on other planets? The Earth might be able to help with that — specifically with something called the red edge.

    The Green Light for Life

    One of the most exciting prospects of exoplanet science is discovering another planet that can harbor life. However, this necessitates us knowing how to identify life at a distance, which is quite a challenge!

    The light reflected by an exoplanet is one of the most useful observations to have on this quest. The reflected light is dependent on the surface and atmospheric conditions of the planet, and it may hold key features that point to the existence of life. What those features are, however, is another question.

    This is where the Earth comes in handy. With our intimate understanding of the Earth, we can simulate it as an exoplanet fairly accurately. Those simulations can help us better pick out Earth-like planets from reflected-light observations.

    The Earth’s reflected-light spectrum contains a unique feature: something called the red edge, a region of rapid change in the near-infrared part of the spectrum. The red edge is caused by chlorophyll in the Earth’s organisms, which has the quirk of strongly reflecting red light. Could this red edge be used to identify chlorophyll-containing life on other planets? In a recent study, Jack O’Malley-James and Lisa Kaltenegger (Carl Sagan Institute, Cornell University) considered the effects of various organisms on the red edge and what that means for the red edge’s detectability.

    Exploring Scenarios

    A surprising number of organisms contain chlorophyll, but at present, land-based vegetation is most responsible for the red edge. Aside from trees (a catchall term for land-based vegetation), O’Malley-James and Kaltenegger considered other organisms like cyanobacteria, algae, and lichens.

    Initially, the authors used a simplified model of the Earth to understand the impact of each organism. They assumed that the entirety of the planet was covered by just one organism and determined how the red edge would appear for an atmosphere that was still like the Earth’s. They then tried the same scenario with a more realistic Earth, which had a surface that was 30% land and 70% ocean.

    The authors also considered the effect of clouds. They tried two cases for each planet scenario, one with clear skies and the other with 60% cloud cover. The difference in cloud cover was more significant for the realistic planet model.

    2
    The fraction of light reflected at different wavelengths by different chlorophyll-containing organisms (corals; trees; elysia viridis, a photosynthetic sea slug; lichens; algae; cyanobacteria). The gray area shows the wavelength range in which the red peak appears. [O’Malley-James and Kaltenegger 2019]

    Earths at Different Times

    The red edge likely evolved with life on the Earth. Trees are relative newcomers, having only established themselves ~500–725 million years ago. Algae and lichens are much older — ~1 billion years old — and cyanobacteria likely appeared at least 2 billion years ago. These staggered arrival times imply that planets that are similar to the early Earth could still produce red edges.

    There may not be a lot of planets exactly like the present-day Earth, but O’Malley-James and Kaltenegger suggest that this isn’t a setback. We could potentially identify planets that have just begun to harbor life — and that’s a big step in the right direction.

    Citation

    “Expandinghttps://iopscience.iop.org/article/10.3847/2041-8213/ab2769 the Timeline for Earth’s Photosynthetic Red Edge Biosignature,” Jack T. O’Malley-James and Lisa Kaltenegger 2019 ​ApJL​ ​879​ L20.
    https://iopscience.iop.org/article/10.3847/2041-8213/ab2769

    See the full article here .


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    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 12:35 pm on October 2, 2019 Permalink | Reply
    Tags: , , , , Exoplanet research, MAROON-X,   

    From University of Chicago: “Nearly a decade in the making, exoplanet-hunting instrument installed in Hawaii” 

    U Chicago bloc

    From University of Chicago

    1
    MAROON-X is now one of the instruments in rotation at the Gemini Observatory, located on Mauna Kea in Hawaii. Photo courtesy of Jacob Bean

    Oct 2, 2019
    Louise Lerner

    Built by UChicago scientists, MAROON-X will search for worlds in other solar systems.

    MAROON-X Exoplanet hunter FROM Bean Exoplanet Group at U Chicago

    Atop a dormant volcano in Hawaii, an extremely delicate instrument—designed to help scientists find distant worlds—is scattered across the floor in hundreds of pieces.

    “Imagine trying to assemble one of those huge LEGO sets, except there’s no instruction book; you’ve done it once before, but then you had to take it all apart and put it in little bags,” said Jacob Bean, associate professor of astronomy and astrophysics at the University of Chicago. “Also you’re at 14,000 feet, and when the air is that thin it impairs your judgment and thinking, and so here you are working 12-hour shifts lifting heavy things but also trying to put together a delicate instrument.”

    This was Bean’s task as the head of a UChicago project to build and install an innovative instrument that will scan the skies for new exoplanets—worlds in other solar systems that could potentially host life. Over the past eight years, Bean and his team had designed and built the instrument, called MAROON-X; this summer they finally attached it to a telescope at the Gemini Observatory at the top of Mauna Kea, Hawaii.

    2
    MAROON-X team members and Gemini Observatory staff standing in front of the Gemini North telescope with the MAROON-X unit. (From left): Paul McBride, John Randrup, Rody Kawaihae, Harlan Uehara, and Eduardo Tapia of Gemini Observatory; MAROON-X team members Andreas Seifahrt, David Kasper and Julian Stürmer; as well as Alison Peck, and John White of Gemini Observatory. Image courtesy of Andreas Seifahrt

    “It has been a pretty intense six months for my team to commission this instrument,” said Bean, an expert in faraway worlds whose research focuses on discovering and examining potentially habitable planets in other solar systems. “But in the next 10 years we’re going to learn things about habitable worlds that we’d never known before. It’s going to be really transformative.”

    Several decades ago, advances in technology allowed scientists to begin detecting the very faint signatures from planets orbiting other stars in faraway solar systems. There’s been an explosion of discoveries; currently, NASA lists 4,000 confirmed exoplanets and thousands more candidates.

    However, we still have no confirmed Earth-like exoplanets with habitable surface conditions. The thing about Earth-like planets, which is why it is taking so long to be able to find and characterize them, is that they’re extremely hard to see. Because these planets are circling around a star that is at least a million times brighter than they are, trying to look directly for them is like trying to see a lightning bug next to a lighthouse that is on the other side of the country. So scientists have to find indirect ways of finding them based on the effects they have on their stars.

    MAROON-X does this by noticing the extremely tiny gravitational tug that an exoplanet (or two, or five, or seven) exerts on its star as it orbits around it. This tug causes the star to wobble just the slightest bit in its orbit. But that’s enough motion to catch it.

    Attached to the Gemini North telescope, MAROON-X takes all the light gathered by the 25-foot telescope and focuses it down to a spot that is the width of a human hair. Then it separates out that light into the different colors of the rainbow and reads the intensity of each band. The color of the light will change slightly as the star moves forward or back. “It’s kind of like a radar gun for stars,” Bean said.

    4
    The first light image from MAROON-X, with added color to visualize for the human eye. The instrument separates out light from the telescope and reads the intensity of each band, which will change slightly if a star has a planet pulling on its gravitational orbit. Image courtesy of Andreas Seifahrt

    By catching this wobble, scientists can calculate the mass of the hidden planet (or planets) pulling on the star.

    The precision needed for this, of course, is incredible. “When the light hits our detector, that shift is beyond imperceptible to the human eye. It’s a thousandth of a pixel. It’s approaching the size of the silicon atoms in the detector,” Bean said. “This is a star that is faint even for big telescopes. And we can tell if it’s moving towards or away from us at a rate comparable to human walking speed—that is, a few feet per second.”

    “The changes that we’re looking for are so tiny that every night before we observe, we have to re-calibrate the instrument,” said research scientist Andreas Seifahrt, who built MAROON-X with Bean.

    ‘It’s really been a labor of love’

    6
    Associate professor Jacob Bean (left) and research associate professor Andreas Seifahrt working on MAROON-X, a new instrument to look for planets beyond the solar system. Photo courtesy of Alison Peck

    Once they were satisfied with the instrument’s performance, then came the painstaking—and terrifying—work to transport it from Chicago to Hawaii. “Spending eight years on this instrument and then watching from the loading dock as the truck drives away with it and you won’t see it until two weeks later at the top of a mountain across an ocean—it’s pretty nerve-wracking,” Seifahrt said.

    But the crates with the equipment made it safely to Hawaii, where Bean, Seifahrt, and postdocs Julian Stürmer and David Kasper got their LEGO set assembled. On September 23, MAROON-X took its official first-light readings.

    The instrument will work in concert with NASA’s Transiting Exoplanet Survey Satellite (TESS) to get a full picture of candidate exoplanets.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    TESS looks for the dimming of the light as a planet crosses in front of a star, so scientists can find how big it is. By combining that with MAROON-X’s mass data, you can calculate an exoplanet’s density—which tells you if you’re looking at a rocky planet, like Earth, or a gaseous one, like Jupiter.

    MAROON-X also will be able to detect signatures from the atmosphere of the planet, such as its composition and thickness.

    “Long-term, we hope to be able to look for biosignatures—things that would only exist if life put them there,” Bean said. “For example, in Earth’s atmosphere, we only have oxygen because it was put there by plants. It’s a puzzle with a lot of different pieces.”

    As they gather new data, Bean expects to work with UChicago colleagues including planetary composition experts Leslie Rogers, Dorian Abbott and Edwin Kite, and crack exoplanet hunter Daniel Fabrycky, to turn the readings into predictions about the faraway exoplanets. Soon, too, NASA’s James Webb Space Telescope will launch as the successor to Hubble, bringing even more imaging capabilities to bear on the question.

    In addition to Bean, Seifahrt, Stürmer, and Kasper, multiple generations of UChicago undergraduate students, graduate students and postdoctoral researchers worked on MAROON-X. “It’s really been a labor of love for my team,” Bean said, “and now it’s finally real. It’s a very exciting time.”

    Seifahrt agreed: “Pulling this off with such a small team and a limited budget is really an achievement. Looking back, it was kind of an insane thing to do—but we think it’s really going to be a trailblazing instrument.”

    Funding: The David and Lucile Packard Foundation, the Heising-Simons Foundation, the Gemini Observatory, and the University of Chicago

    See the full article here .

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    U Chicago Campus

    An intellectual destination

    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

    The University of Chicago is an urban research university that has driven new ways of thinking since 1890. Our commitment to free and open inquiry draws inspired scholars to our global campuses, where ideas are born that challenge and change the world.

    We empower individuals to challenge conventional thinking in pursuit of original ideas. Students in the College develop critical, analytic, and writing skills in our rigorous, interdisciplinary core curriculum. Through graduate programs, students test their ideas with UChicago scholars, and become the next generation of leaders in academia, industry, nonprofits, and government.

    UChicago research has led to such breakthroughs as discovering the link between cancer and genetics, establishing revolutionary theories of economics, and developing tools to produce reliably excellent urban schooling. We generate new insights for the benefit of present and future generations with our national and affiliated laboratories: Argonne National Laboratory, Fermi National Accelerator Laboratory, and the Marine Biological Laboratory in Woods Hole, Massachusetts.

    The University of Chicago is enriched by the city we call home. In partnership with our neighbors, we invest in Chicago’s mid-South Side across such areas as health, education, economic growth, and the arts. Together with our medical center, we are the largest private employer on the South Side.

    In all we do, we are driven to dig deeper, push further, and ask bigger questions—and to leverage our knowledge to enrich all human life. Our diverse and creative students and alumni drive innovation, lead international conversations, and make masterpieces. Alumni and faculty, lecturers and postdocs go on to become Nobel laureates, CEOs, university presidents, attorneys general, literary giants, and astronauts.

     
  • richardmitnick 11:25 am on August 30, 2019 Permalink | Reply
    Tags: "Life on alien worlds could be more diverse than on Earth", , , , , , Exoplanet research   

    From Astronomy Magazine: “Life on alien worlds could be more diverse than on Earth” 

    Astronomy magazine

    From Astronomy Magazine

    August 23, 2019
    Mara Johnson-Groh

    Earth is the only place in the universe where we know life exists. But with billions of other star systems out there, it might not be the best place for life.

    1
    When you stack up the most promising recent exoplanet finds, as illustrated here, it becomes clear none is Earth’s true twin. But even more habitable worlds may be out there waiting to be found. NASA/Ames/JPL-Caltech

    Earth is the only place in the universe where we know life exists. But with billions of other star systems out there, it might not be the best place for life. In a new study [Goldschmidt2019 Barcelona], astronomers modeled the potential for life on other watery planets and found some conditions that can create oceans maximized for habitability.

    The model suggests that watery planets with dense atmospheres, continents, and long days — slowly rotating planets that is — were most conducive to life. These conditions stimulate ocean circulation, which brings nutrients from the depths to the surface where it’s available for biologic activity.

    “The research shows us that conditions on some exoplanets with favorable ocean circulation patterns could be better suited to support life that is more abundant or more active than life on Earth,” Stephanie Olson, a University of Chicago researcher who lead the new study, said in a press release.

    To date, over 4,000 exoplanets have been confirmed, and a handful of those worlds orbit at a safe enough distance from their host star to have liquid water on the surface. These habitable zone planets are at the forefront of the search for alien life and the new research, presented Friday at the Goldschmidt Conference in Barcelona, Spain, will help astronomers narrow down that search.

    Previous studies looking at exoplanet habitability had largely neglected the role that oceans play in regulating global climate and heat transportation. The researchers focused in on this niche, using a computer model to compare different combinations of climates and ocean habitats that could exist on exoplanets across the galaxy. The study aimed to look for things like upwelling, a type of ocean circulation driven by wind.

    Upwelling and ocean circulation have long played a major role in sustaining life in Earth’s oceans. And since the oceans and atmospheres are interlinked, the evolution of life in the oceans has been reflected in certain chemical changes in the atmosphere. It’s unlikely astronomers will directly see life on other planets, but seeing these so-called biosignatures in exoplanet atmospheres could be possible with the next generation of telescopes. Ultimately, this research will help scientists select the best candidates out of the growing census of exoplanets for follow up study.

    “One of the things we don’t really understand particularly well in the exoplanet community is how oceans on some of these planets might be working,” said Chris Reinhard, professor at the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, who was not involved in the new study. “Part of that is because we haven’t had the computer models or people working on them to really explore these things, so there’s a lot to learn. This is a really huge step in the right direction to figure some of those things out.”

    See the full article here .


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  • richardmitnick 9:19 pm on August 29, 2019 Permalink | Reply
    Tags: , , ‘Alopeke/Zorro, , , Exoplanet research,   

    From Gemini Observatory: “Exoplanets Can’t Hide Their Secrets from Innovative New Instrument” 

    NOAO

    Gemini Observatory
    From Gemini Observatory

    August 29, 2019

    Media Contacts:

    Peter Michaud
    Public Information and Outreach Manager
    Gemini Observatory, Hilo, HI
    email: pmichaud”at”gemini.edu
    Desk: (808) 974-2510
    Cell: (808) 936-6643

    Alyssa Grace
    Public Information and Outreach Assistant
    Gemini Observatory, Hilo, HI
    email: agrace”at”gemini.edu
    Desk: (808) 974-2531

    Science Contacts:

    Steve B. Howell
    Space Science and Astrobiology Division
    NASA Ames Research Center, Moffett Field, CA
    email: steve.b.howell”at”nasa.gov
    Desk: (650) 604-4238
    Cell: (520) 461-6925

    Andrew Stephens
    Instrument Scientist
    Gemini Observatory, Hilo, HI
    email: astephens”at”gemini.edu
    Desk: (808) 974-2611

    In an unprecedented feat, an American research team discovered hidden secrets of an elusive exoplanet using a powerful new instrument at the 8-meter Gemini North telescope on Maunakea in Hawai‘i [below]. The findings not only classify a Jupiter-sized exoplanet in a close binary star system, but also conclusively demonstrate, for the first time, which star the planet orbits.

    The breakthrough occurred when Steve B. Howell of the NASA Ames Research Center and his team used a high-resolution imaging instrument of their design — named ‘Alopeke (a contemporary Hawaiian word for Fox).

    2
    ‘Alopeke at Gemini North

    The team observed exoplanet Kepler-13b as it passed in front of (transited) one of the stars in the Kepler-13AB binary star system some 2,000 light years distant. Prior to this attempt, the true nature of the exoplanet was a mystery.

    3
    Artist’s conception of the Kepler-13AB binary star system as revealed by observations including the new Gemini Observatory data. The two stars (A and B) are large, massive bluish stars (center) with the transiting “hot Jupiter” (Kepler-13b) in the foreground (left corner). Star B and its low mass red dwarf companion star are seen in the background to the right. Credit: Gemini Observatory/NSF/AURA/Artwork by Joy Pollard

    “There was confusion over Kepler-13b: was it a low-mass star or a hot Jupiter-like world? So we devised an experiment using the sly instrument ‘Alopeke,” Howell said. The research was recently published in The Astronomical Journal. “We monitored both stars, Kepler A and Kepler B, simultaneously while looking for any changes in brightness during the planet’s transit,” Howell explained. “To our pleasure, we not only solved the mystery, but also opened a window into a new era of exoplanet research.”

    “This dual win has elevated the importance of instruments like ‘Alopeke in exoplanet research,” said Chris Davis of the National Science Foundation, one of Gemini’s sponsoring agencies. “The exquisite seeing and telescope abilities of Gemini Observatory, as well as the innovative ‘Alopeke instrument made this discovery possible in merely four hours of observations.”

    ‘Alopeke performs “speckle imaging,” collecting a thousand 60-millisecond exposures every minute. After processing this large amount of data, the final images are free of the adverse effects of atmospheric turbulence — which can bloat, blur, and distort star images.

    “About one half of all exoplanets orbit a star residing in a binary system, yet, until now, we were at a loss to robustly determine which star hosts the planet,” said Howell.

    The team’s analysis revealed a clear drop in the light from Kepler A, proving that the planet orbits the brighter of the two stars. Moreover, ‘Alopeke simultaneously provides data at both red and blue wavelengths, an unusual capability for speckle imagers. Comparing the red and blue data, the researchers were surprised to discover that the dip in the star’s blue light was about twice as deep as the dip seen in red light. This can be explained by a hot exoplanet with a very extended atmosphere, which more effectively blocks the light at blue wavelengths. Thus, these multi-color speckle observations give a tantalizing glimpse into the appearance of this distant world.

    Early observations once pointed to the transiting object being either a low-mass star or a brown dwarf (an object somewhere between the heaviest planets and the lightest stars). But Howell and his team’s research almost certainly shows the object to be a Jupiter-like gas-giant exoplanet with a “puffed up” atmosphere due to exposure to the tremendous radiation from its host star.

    ‘Alopeke has an identical twin at the Gemini South telescope in Chile [below], named Zorro, which is the word for fox in Spanish. Like ‘Alopeke, Zorro is capable of speckle imaging in both blue and red wavelengths. The presence of these instruments in both hemispheres allows Gemini Observatory to resolve the thousands of exoplanets known to be in multiple star systems.

    “Speckle imaging is experiencing a renaissance with technology like fast, low noise detectors becoming more easily available,” said team member and ‘Alopeke instrument scientist Andrew Stephens at the Gemini North telescope. “Combined with Gemini’s large primary mirror, ‘Alopeke has real potential to make even more significant exoplanet discoveries by adding another dimension to the search.”

    First proposed by French astronomer Antoine Labeyrie in 1970, speckle imaging is based on the idea that atmospheric turbulence can be “frozen” when obtaining very short exposures. In these short exposures, stars look like collections of little spots, or speckles, where each of these speckles has the size of the telescope’s optimal limit of resolution. When taking many exposures, and using a clever mathematical approach, these speckles can be reconstructed to form the true image of the source, removing the effect of atmospheric turbulence. The result is the highest-quality image that a telescope can produce, effectively obtaining space-based resolution from the ground — making these instruments superb probes of extrasolar environments that may harbor planets.

    The discovery of planets orbiting other stars has changed the view of our place in the Universe. Space missions like NASA’s Kepler/K2 Space Telescope and the Transiting Exoplanet Survey Satellite (TESS) have revealed that there are twice as many planets orbiting stars in the sky than there are stars visible to the unaided eyes; to date the total discovery count hovers around 4,000. While these telescopes detect exoplanets by looking for tiny dips in the brightness of a star when a planet crosses in front of it, they have their limits.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018

    NASA/MIT TESS replaced Kepler in search for exoplanets

    “These missions observe large fields of view containing hundreds of thousands of stars, so they don’t have the fine spatial resolution necessary to probe deeper,” Howell said. “One of the major discoveries of exoplanet research is that about one-half of all exoplanets orbit stars that reside in binary systems. Making sense of these complex systems requires technologies that can conduct time sensitive observations and investigate the finer details with exceptional clarity.”

    “Our work with Kepler-13b stands as a model for future research of exoplanets in multiple star systems,” Howell continued. “The observations highlight the ability of high-resolution imaging with powerful telescopes like Gemini to not only assess which stars with planets are in binaries, but also robustly determine which of the stars the exoplanet orbits.”

    See the full article here .


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    NOAO Gemini North on MaunaKea, Hawaii, USA, Altitude 4,213 m (13,822 ft)


    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet


    Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.

    The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope on Cerro Pachón in central Chile (Gemini South); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.

    The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the Canadian National Research Council (NRC), the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT), the Australian Research Council (ARC), the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.

     
  • richardmitnick 11:28 am on June 20, 2019 Permalink | Reply
    Tags: "Two Planets Straddling the Gap", , , , , , Exoplanet research   

    From AAS NOVA: “Two Planets Straddling the Gap” 

    AASNOVA

    From AAS NOVA

    19 June 2019
    Susanna Kohler

    1
    We’ve observed a diverse range of planets larger than Earth (a few are shown in these illustrations), but they tend to fall into two size categories: super-Earth or mini-Neptune. [NASA Ames/JPL-Caltech]

    As of last week, the count of confirmed exoplanets officially exceeds 4,000 — and while we’ve learned a lot about planet formation from this wealth of data, it’s also prompted new questions. Could the recent detection of two intriguing new planets shed light on one of these open puzzles?

    2
    In 2017, a team of scientists led by B.J. Fulton identified a gap in the distribution of radii of small Kepler-discovered planets. [NASA/Ames/Caltech/University of Hawaii (B. J. Fulton]

    Mind the Gap

    Our growing exoplanet statistics recently revealed a curious trait: there’s a gap in the radius distribution of planets slightly larger than Earth. Rocky super-Earth planets of up to ~1.5 Earth radii are relatively common, as are gaseous mini-Neptunes in the range of ~2–4 Earth radii. But we’ve detected very few planets in between these sizes.

    What’s the cause of this odd deficit? One theory is that high-energy radiation emitted by stars early in their lifetimes erodes the atmospheres of planets that are too close in, stripping them of their expansive shells of gas and leaving behind only their dense, rocky cores. Planets that lie further out or start with a thicker shell may be spared this fate, retaining some of their gas for a significantly larger, fluffier construction.

    3
    Folded light curves for HD 15337 showing the transits of planets b (top) and c (bottom). [Gandolfi et al. 2019]

    Disentangling Factors

    This theory can be difficult to test, however, due to the large number of intertwined variables. The super-Earths and mini-Neptunes we’ve observed lie at varying distances from their host stars — but they also orbit around different types of stars with very different radiation histories. It’s hard to tell what role these various factors play in the planets’ evolution.

    But a recent discovery from the Transiting Exoplanet Survey Satellite (TESS) may help simplify this picture. With more than 750 planet-candidate detections so far, TESS is rapidly adding to our exoplanet statistics — and two TESS-discovered planets around HD 15337 may be especially useful for better understanding the radius gap.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    A Non-Identical Pair

    In a publication led by Davide Gandolfi (University of Turin, Italy), a team of scientists carefully analyzes the TESS light curves for HD 15337, as well as archival spectroscopic data from the High Accuracy Radial velocity Planet Searcher. They show that there is evidence for the presence of two planets — HD 15337 b and c — that have similar masses: ~7.5 and ~8.1 Earth masses, respectively.

    But while HD 15337 b appears to be a close-in (period of 4.8 days), rocky super-Earth with radius of 1.6 Earth radii and density of 9.3 g/cm3, HD 15337 c lies further out (period of 17.2 days) and is a fluffy mini-Neptune, with a radius of 2.4 Earth radii and a density of 3.2 g/cm3.

    Since these two planets orbit the same star, it seems likely that their different orbital radii are what led to their places on either side of the radius gap. Using a planet atmospheric evolution algorithm, Gandolfi and collaborators show that the properties of the two planets can be produced by high-energy radiation from HD 15337 early in the system’s lifetime.

    As our observational statistics for exoplanets continue to grow, it’s exciting to see how these continued discoveries can both raise and address new questions of planet formation and evolution. Who knows what else we’ll learn as detections continue to pile up!

    Citation

    “The Transiting Multi-planet System HD15337: Two Nearly Equal-mass Planets Straddling the Radius Gap,” Davide Gandolfi et al 2019 ApJL 876 L24.
    https://iopscience.iop.org/article/10.3847/2041-8213/ab17d9

    See the full article here .


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    Please help promote STEM in your local schools.

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    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 10:02 am on May 13, 2019 Permalink | Reply
    Tags: , Exoplanet research, , NASA’s Astrobiology Program, NExSS 2.0, Nexus for Exoplanet System Science or “NExSS”, Signatures of life on distant planets, Teams from seventeen academic and NASA centers   

    From Many Worlds: “NExSS 2.0” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    May 13, 2019
    Marc Kaufman

    1
    Finding new worlds can be an individual effort, a team effort, an institutional effort. The same can be said for characterizing exoplanets and understanding how they are affected by their suns and other planets in their solar systems. When it comes to the search for possible life on exoplanets, the questions and challenges are too great for anything but a community. NASA’s NExSS initiative has been an effort to help organize, cross-fertilize and promote that community. This artist’s concept Kepler-47, the first two-star systems with multiple planets orbiting the two suns, suggests just how difficult the road ahead will be. ( NASA/JPL-Caltech/T. Pyle)

    The Nexus for Exoplanet System Science, or “NExSS,” began four years ago as a NASA initiative to bring together a wide range of scientists involved generally in the search for life on planets outside our solar system.

    With teams from seventeen academic and NASA centers, NExSS was founded on the conviction that this search needed scientists from a range of disciplines working in collaboration to address the basic questions of the fast-growing field.

    Among the key goals: to investigate just how different, or how similar, different exoplanets are from each other; to determine what components are present on particular exoplanets and especially in their atmospheres (if they have one); to learn how the stars and neighboring exoplanets interact to support (or not support) the potential of life; to better understand how the initial formation of planets affects habitability, and what role climate plays as well.

    Then there’s the question that all the others feed in to: what might scientists look for in terms of signatures of life on distant planets?

    Not questions that can be answered alone by the often “stove-piped” science disciplines — where a scientist knows his or her astrophysics or geology or geochemistry very well, but is uncomfortable and unschooled in how other disciplines might be essential to understanding the big questions of exoplanets.

    2
    The original NExSS team was selected from groups that had won NASA grants and might want to collaborate with other scientists with overlapping interests and goals but often from different disciplines. (NASA)

    The original idea for this kind of interdisciplinary group came out of NASA’s Astrobiology Program, and especially from NASA astrobiology director Mary Voytek and colleague Shawn Domogal-Goldman. It was something of a gamble, since scientists who joined would essentially volunteer their time and work and would be asked to collaborate with other scientists in often new ways.

    But over the past four years NExSS has proven itself to be very active and useful in terms of laying out strategies for tackling the biggest questions in the field of exoplanets and whether they might harbor life. In two major reports last year, the private, congressionally-mandated National Academies of Sciences, Engineering and Medicine held up NExSS as a successful model for moving the science forward.

    One of the study co-chairs, David Charbonneau of Harvard University, said after the release of the study that the “promise of NExSS is tremendous…We really want that idea to grow and have a huge impact.”

    3
    This major report from the National Academy of Sciences last year endorsed NExSS as a program that substantially aided the exoplanet community. The report recommended that the organization be expanded. (NAS)

    So with that kind of affirmation, it was hardly surprising that the first gathering of a newly constituted NExSS at the University of California, Santa Cruz featured 34 teams, double the original 17. (The team members, both new and original, are here.)

    As explained at the opening of the gathering by Voytek and others, the NExSS approach is all about creating, expanding and promoting the fast-growing fields of exoplanet habitability and astrobiology more generally.

    “The original NExSS members were in service to all of you,” she told the group. “They provided the opportunity to help your community to push questions further and also to get NASA headquarters to give some necessary attention to what you are doing.”

    And in many ways they succeeded. The NExSS teams may not have gotten funded additionally for their work, but the group’s rising profile created important advisory opportunities for participants.

    From the first NExSS groups, for instance, scientists were selected for leadership roles in the main exoplanet science group and several for science and technology definition teams. These groups established by NASA are putting together four proposals for a grand observatory for the 2030s — a hoped-for successor to the Hubble Space Telescope and the James Webb Space Telescope.

    NExSS members also were called on to organize in-depth workshops on subjects ranging from defining and interpreting biosignatures on distant planets, to the centrality of exoplanet interiors and most recently to what signs of advanced technological civilizations might be detectable. Major white papers were generally written, submitted and published in journals following these NExSS workshops.

    “I think putting together NExSS is most successful thing I’ve done in my career in NASA,” said Voytek who, in her decade-plus at the agency, has worked to change attitudes about astrobiology and interdisciplinary work. “I’m proud of what you did and we did.”

    What’s more, as Voytek explained at the beginning of the meeting, the NExSS approach will spread with the creation of four new networking groups based on the model of NExSS.

    They will use the same cross-disciplinary, get-to-know-your-fellow scientists approach to jump-start collaborations and cross-fertilizing in other aspects of the search for life beyond Earth, as well as the effort to understand how life on Earth (and potentially elsewhere) might have started and grown more complex.

    (The four, below, focus on planetary chemistry before life, on biosignatures, on the transition from early single cell organisms to more complex ones, and on what can be learned from ocean worlds.)

    This expansion, which will be part of a reorganization of NASA’s astrobiology program, will change the way that science teams will be funded and also, as Voytek put it, would “democratize” the process that NExSS began. The original program had selected many of its principal investigators from large teams and organizations, but the expanded NExSS and the four other groups to come will be more widely open to teams and individuals from smaller institutions who are earlier in their careers.

    This is important, Voytek and other NExSS organizers said, because the NExSS approach allows scientists to network in ways that create science opportunities, as well as those avenues into the major prioritizing organizations in their exoplanet/astrobiology community writ large.

    3

    One value of this approach can be seen in the person of planetary scientist Sarah Morrison, a postdoc at the large Pennsylvania State University exoplanet program who has been hired to teach at the much smaller Missouri State University program.

    3

    She is a co-principal investigator on one of two NExSS teams at Penn State and was at last week’s Santa Cruz meeting in that capacity.

    Her research focuses on protoplanetary disks and planet formation within them. In particular, she studies the many different types of interactions — collisions, migrations, atmosphere losses — that forming planets can have within their natal disks. She is also intrigued by solar systems where the planets orbit in resonance to each other.

    These factors, and many others, have implications for the composition of planets and then for the possibility of life starting on them. Factors such as the eccentricity of a planet’s orbit or where it was formed within the disk can make a planet a good candidate for habitability or one where life is impossible.

    For Morrison, NExSS is an avenue for keeping her research vibrant.

    “I’m going to a smaller institution, with not so many people doing exoplanets,” she told me. “For me to remain active in the field and work, and to have the collaborators I need to open possibilities for students working with me, this type of network can be very important – on the research side and education side.”

    She said that it isn’t always easy to find scientists whose work overlaps with hers, but that at the NExSS meeting it was easy.

    “I can definitely see projects down the line as a result of conversations I had with those folks,” she said. “And developing collaborations now is very important to me.”

    As described by Voytek and other NExSS leaders, another major focus of the group has been to encourage NASA headquarters to embrace some of the interdisciplinary approach they practice and are convinced is necessary.

    This is part of a much longer effort by Voytek and other to include the search for life beyond Earth in the missions large and small that NASA develops. There was certainly resistance at times, but the agency has, in the past decade, made that search an increasingly central NASA goal.

    As described by NExSS leader (or “Jedi”) Dawn Gelino, deputy director of the agency’s Exoplanet Science Institute, NASA headquarters has responded in other ways as well, and in recent months made two of its major research grant programs interdivisional.

    That means scientists from quite different but nonetheless related disciplines can — for the first time — together propose projects for funding by those NASA programs. Thomas Zurbuchen, NASA’s associate administrator of the Science Mission Directorate, has been forceful in his support for this kind of approach.

    “As a result of NExSS, we are definitely making a difference at headquarters in terms of the structure of teams responding to calls for proposals,” Gelino said.

    A NExSS interdisciplinary approach is not for everyone, and some question its value. Many researchers would prefer to spend their time at the telescope, in the lab, with their modeling computers, writing papers — with laser focus on their areas of expertise. NExSS leaders regularly make the point that those decisions are understood and perfectly fine.

    But especially in inherently interdisciplinary fields such as exoplanets and astrobiology, the pool of scientists willing to pitch in to advance the community appears to be large and has proven go be quite useful.

    (Since I am writing about NExSS, I want to be clear in saying that the program helps support Many Worlds. A second column about NExSS brain-storming about the future of exoplanet and habitability studies will be coming soon.)

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds
    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 11:13 am on April 16, 2019 Permalink | Reply
    Tags: "Astronomers Have Found Potential Life-Supporting Conditions on The Nearest Exoplanet", , , , Carl Sagan Institute, , , Exoplanet research,   

    From Carl Sagan Institute via Science Alert: “Astronomers Have Found Potential Life-Supporting Conditions on The Nearest Exoplanet” 

    From Carl Sagan Institute

    via

    ScienceAlert

    Science Alert

    16 APR 2019
    MATT WILLIAMS

    1
    Artist impression of an exoplanet from its moon. (IAU/L. Calçada)

    In August of 2016, astronomers from the European Southern Observatory (ESO) announced the discovery of an exoplanet in the neighboring system of Proxima Centauri. The news was greeted with considerable excitement, as this was the closest rocky planet to our Solar System that also orbited within its star’s habitable zone.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    Since then, multiple studies have been conducted to determine if this planet could actually support life.

    Unfortunately, most of the research so far has indicated that the likelihood of habitability are not good. Between Proxima Centauri’s variability and the planet being tidally-locked with its star, life would have a hard time surviving there.

    However, using lifeforms from early Earth as an example, a new study [MNRAS] conducted by researchers from the Carl Sagan Institute (CSI) has shows how life could have a fighting chance on Proxima b after all.

    2
    Artist’s impression of Proxima b’s surface, orbiting the red dwarf star. (ESO)

    The study, which recently appeared in the Monthly Notices of the Royal Astronomical Society [link is above], was conducted by Jack O’Malley-James and Lisa Kaltenegger – an research associate and the director of the Carl Sagan Institute at Cornell University.

    Together, they examined the levels of surface UV flux that planets orbiting M-type (red dwarf) stars would experience and compared that to conditions on primordial Earth.

    The potential habitability of red dwarf systems is something scientists have been debated for decades. On the one hand, they have a number of attributes that are encouraging, not the least of which is their commonality.

    Essentially, red dwarfs are the most common type of star in the Universe, accounting for 85 percent of the stars in the Milky Way alone.

    They also have the greatest longevity, with lifespans that can last into the trillions of years. Last, but not least, they appear to be the most likely stars to host systems of rocky planets.

    This is attested to by the sheer number of rocky planets discovered around neighboring red dwarf stars in recent years – such as Proxima b, Ross 128b, LHS 1140b, Gliese 667Cc, GJ 536, the seven rocky planets orbiting TRAPPIST-1.

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA


    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile


    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    However, red dwarf stars also present a lot of impediments to habitability, not the least of which is their variable and unstable nature. As O’Malley-James explained to Universe Today via email:

    “The chief barrier to the habitability of these worlds is the activity of their host stars. Regular stellar flares can bathe these planets in high levels of biologically harmful radiation. Furthermore, over longer periods of time, the onslaught of X-ray radiation and charged particle fluxes from the host stars places the atmospheres of these planets at risk of being stripped away over time if a planet cannot replenish its atmosphere fast enough.”

    For generations, scientists have struggled with questions regarding the habitability of planets that orbit red dwarf stars.

    Unlike our Sun, these low-mass, ultra-cool dwarf stars are variable, unstable and prone to flare-ups. These flares release a lot of high-energy UV radiation, which is harmful to life as we know it and capable of stripping a planet’s atmospheres away.

    This places significant limitations on the ability of any planet orbiting a red dwarf star to give rise to life or remain habitable for long. However, as previous studies have shown, much of this depends on the density and composition of the planets’ atmospheres, not to mention whether or not the planet has a magnetic field.

    To determine if life could endure under these conditions, O’Malley-James and Kaltenegger considered what conditions were like on planet Earth roughly 4 billion years ago.

    At that time, Earth’s surface was hostile to life as we know it today. In addition to volcanic activity and a toxic atmosphere, the landscape was bombarded by UV radiation in a way that is similar to what planets that orbit M-type stars experience today.

    To address this, Kaltenegger and O’Malley-James modeled the surface UV environments of four nearby “potentially habitable” exoplanets – Proxima-b, TRAPPIST-1e, Ross-128b and LHS-1140b – with various atmospheric compositions. These ranged from ones similar to present-day Earth to those with “eroded” or “anoxic” atmospheres – i.e. those that don’t block UV radiation well and don’t have a protective ozone layer.

    These models showed that as atmospheres become thinner and ozone levels decrease, more high-energy UV radiation is able to reach the ground. But when they compared the models to what was present on Earth, roughly 4 billion years ago, the results proved interesting. As O’Malley-James said:

    “The unsurprising result was that the levels of surface UV radiation were higher than we experience on Earth today. However, the interesting result was that the UV levels, even for the planets around the most active stars, were all lower than the Earth experienced in its youth. We know the young Earth supported life, so the case for life on planets in M star systems may not be quite so dire after all.”

    What this means, in essence, is that life could exist on neighboring planets like Proxima b right now despite being subjected to harsh levels of radiation. If you consider the age of Proxima Centauri – 4.853 billion years, which is roughly 200 million years older than our Sun – the case for potential habitability may become even more intriguing.

    The current scientific consensus is that the first lifeforms on Earth emerged a billion years after the planet formed (3.5 billion years ago). Assuming Proxima b formed from a protoplanetary debris disk shortly after Proxima Centauri was born, life would have had enough time to not only emerge, but get a significant foothold.

    While that life may consist solely of single-celled organisms, it is encouraging nonetheless. Aside from letting us know that there could very well be life beyond our Solar System, and on nearby planets, it provides scientists with constraints on what type of biosignatures may be discernible when studying them. As O’Malley-James concluded:

    “The results from this study builds the case for focusing on life on Earth a few billion years ago; a world of single-celled microbes – prokaryotes – that lived with high UV radiation levels. This ancient biosphere may have the best overlaps with conditions on habitable planets around active M stars, so could provide us with the best clues in our search for life in these star systems.”

    As always, the search for life in the cosmos begins with the study of Earth, since it is the only example we have of a habitable planet. It is therefore important to understand how (i.e. under what conditions) life was able to survive, thrive and respond to environmental changes throughout Earth’s geological history.

    For while we may know of only one planet that supports life, that life has been remarkably diverse and has changed drastically over time.

    Be sure to check out this video about these latest findings, courtesy of the CSI and Cornell University:

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Carl Sagan Institute (CSI) was founded to find life in the universe. Based on the pioneering work of Carl Sagan at Cornell, our interdisciplinary team is developing the forensic toolkit to find life in the universe, inside the Solar System and outside of it, on planets and moons orbiting other stars.

    Recent scientific results show that in our galaxy alone there are billions of planets orbiting other suns. After billions of years of evolution on our own Pale Blue Dot and thousands of years of questioning, we finally have the technology in hand to explore other worlds inside and outside of our solar system. The information generated by the search for signs of life on other worlds also helps us understand and safeguard our own planet — our Pale Blue Dot — better.

    CSI for the search of life in the universe: CSI explores factors that determine if a planet or moon can host life and how we could find it by bringing together experts from a wide range of disciplines, from sciences, engineering to media who work together with some of the planet’s most talented students at the undergraduate, graduate and postdoctoral level. CSI researchers use the latest data from space telescopes, probes to the solar system’s diverse worlds, field and satellite data on our home planet, laboratory studies of terrestrial organisms, and modeling of complex processes from the astronomical to the biological to explore these profound questions. And CSI researchers participate in the development of the next generation of space- and Earth-based facilities to probe ever deeper and farther.

    CSI also interprets these results for the widest possible audience, sharing the fascination of science with everyone who is interested in where humankind stands in the quest to understand our place in the cosmos.

    HISTORY

    The Carl Sagan Institute was founded in 2015 at Cornell University to find life in the universe and explore other worlds – how they form, evolve and if they could harbor life both inside and outside of our own Solar System. Directed by astronomer Lisa Kaltenegger, the Institute has built an entirely new research group, spanning 14 departments at Cornell and including more than 25 faculty who focus on a wide range of the search for life in the universe interdisciplinarily.

    The research group is embedded in a rich environment of established international interdisciplinary cooperation at Cornell. The Institute’s collaboration brings together researchers from fields as far apart as astrophysics, engineering, earth and atmospheric science, geology and biology to tackle questions as diverse as those about the astronomical context of the emergence of life on Earth, how to find it and what this discovery would mean for humankind.

     
  • richardmitnick 4:44 pm on April 1, 2019 Permalink | Reply
    Tags: , , , , , Exoplanet research, , The planet TOI 197.01 (TOI is short for “TESS Object of Interest”)   

    From Iowa State University: “Data flows from NASA’s TESS Mission, leads to discovery of Saturn-sized planet” 

    From Iowa State University

    Mar 27, 2019

    Steve Kawaler
    Physics and Astronomy
    515-294-9728
    sdk@iastate.edu

    Mike Krapfl
    News Service
    515-294-4917
    mkrapfl@iastate.edu

    1
    A “hot Saturn” passes in front of its host star in this illustration. Astronomers who study stars used “starquakes” to characterize the star, which provided critical information about the planet. See a video illustration of the planet orbiting the star. llustration by Gabriel Perez Diaz, Instituto de Astrofísica de Canarias.

    Astronomers who study stars are providing a valuable assist to the planet-hunting astronomers pursuing the primary objective of NASA’s new TESS Mission.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    In fact, asteroseismologists – stellar astronomers who study seismic waves (or “starquakes”) in stars that appear as changes in brightness – often provide critical information for finding the properties of newly discovered planets.

    This teamwork enabled the discovery and characterization of the first planet identified by TESS for which the oscillations of its host star can be measured.

    The planet – TOI 197.01 (TOI is short for “TESS Object of Interest”) – is described as a “hot Saturn” in a recently accepted scientific paper [The Astronomical Journal by an international team of 141 astronomers. Daniel Huber, an assistant astronomer at the University of Hawaii at Manoa’s Institute for Astronomy, is the lead author of the paper. Steve Kawaler, a professor of physics and astronomy; and Miles Lucas, an undergraduate student, are co-authors from Iowa State University.]. That’s because the planet is about the same size as Saturn and is also very close to its star, completing an orbit in just 14 days, and therefore very hot.

    “This is the first bucketful of water from the firehose of data we’re getting from TESS,” Kawaler said.

    TESS – the Transiting Exoplanet Survey Satellite, led by astrophysicists from the Massachusetts Institute of Technology – launched from Florida’s Cape Canaveral Air Force Station on April 18, 2018. The spacecraft’s primary mission is to find exoplanets, planets beyond our solar system. The spacecraft’s four cameras are taking nearly month-long looks at 26 vertical strips of the sky – first over the southern hemisphere and then over the northern. After two years, TESS will have scanned 85 percent of the sky.

    Astronomers (and their computers) sort through the images, looking for transits, the tiny dips in a star’s light caused by an orbiting planet passing in front of it.

    Planet transit. NASA/Ames

    NASA’s Kepler Mission – a predecessor to TESS – looked for planets in the same way, but scanned a narrow slice of the Milky Way galaxy and focused on distant stars.

    TESS is targeting bright, nearby stars, allowing astronomers to follow up on its discoveries using other space and ground observations to further study and characterize stars and planets. In another paper recently published online by The Astrophysical Journal Supplement Series, astronomers from the TESS Asteroseismic Science Consortium (TASC) identified a target list of sun-like oscillating stars (many that are similar to our future sun) to be studied using TESS data – a list featuring 25,000 stars.

    Kawaler – who witnessed the launch of Kepler in 2009, and was in Florida for the launch of TESS (but a last-minute delay meant he had to miss liftoff to return to Ames to teach) – is on the seven-member TASC Board. The group is led by Jørgen Christensen-Dalsgaard of Aarhus University in Denmark.

    TASC astronomers use asteroseismic modeling to determine a host star’s radius, mass and age. That data can be combined with other observations and measurements to determine the properties of orbiting planets.

    In the case of host star TOI-197, the asteroseismolgists used its oscillations to determine it’s about 5 billion years old and is a little heavier and larger than the sun. They also determined that planet TOI-197.01 is a gas planet with a radius about nine times the Earth’s, making it roughly the size of Saturn. It’s also 1/13th the density of Earth and about 60 times the mass of Earth.

    Those findings say a lot about the TESS work ahead: “TOI-197 provides a first glimpse at the strong potential of TESS to characterize exoplanets using asteroseismology,” the astronomers wrote in their paper.

    Kawaler is expecting that the flood of data coming from TESS will also contain some scientific surprises.

    “The thing that’s exciting is that TESS is the only game in town for a while and the data are so good that we’re planning to try to do science we hadn’t thought about,” Kawaler said. “Maybe we can also look at the very faint stars – the white dwarfs – that are my first love and represent the future of our sun and solar system.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Iowa State University is a public, land-grant university, where students get a great academic start in learning communities and stay active in 800-plus student organizations, undergrad research, internships and study abroad. They learn from world-class scholars who are tackling some of the world’s biggest challenges — feeding the hungry, finding alternative fuels and advancing manufacturing.

    Iowa Agricultural College and Model Farm (now Iowa State University) was officially established on March 22, 1858, by the legislature of the State of Iowa. Story County was selected as a site on June 21, 1859, and the original farm of 648 acres was purchased for a cost of $5,379. The Farm House, the first building on the Iowa State campus, was completed in 1861, and in 1862, the Iowa legislature voted to accept the provision of the Morrill Act, which was awarded to the agricultural college in 1864.

    Iowa State University Knapp-Wilson Farm House. Photo between 1911-1926

    Iowa Agricultural College (Iowa State College of Agricultural and Mechanic Arts as of 1898), as a land grant institution, focused on the ideals that higher education should be accessible to all and that the university should teach liberal and practical subjects. These ideals are integral to the land-grant university.

    The first official class entered at Ames in 1869, and the first class (24 men and 2 women) graduated in 1872. Iowa State was and is a leader in agriculture, engineering, extension, home economics, and created the nation’s first state veterinary medicine school in 1879.

    In 1959, the college was officially renamed Iowa State University of Science and Technology. The focus on technology has led directly to many research patents and inventions including the first binary computer (the ABC), Maytag blue cheese, the round hay baler, and many more.

    Beginning with a small number of students and Old Main, Iowa State University now has approximately 27,000 students and over 100 buildings with world class programs in agriculture, technology, science, and art.

    Iowa State University is a very special place, full of history. But what truly makes it unique is a rare combination of campus beauty, the opportunity to be a part of the land-grant experiment, and to create a progressive and inventive spirit that we call the Cyclone experience. Appreciate what we have here, for it is indeed, one of a kind.

     
  • richardmitnick 1:29 pm on February 19, 2019 Permalink | Reply
    Tags: "First Evidence of a Giant Exoplanet Collision", , , , , , Exoplanet research, Kepler-107 system, Kepler-107b and Kepler-107c, The innermost planet Kepler-107b is about 3.5 times as massive as Earth while Kepler-107c which sits farther out is a whopping 9.4 times as massive as Earth, The researchers argue that the denser planet Kepler-107c likely experienced a massive collision with a third unknown planet at some point in its past, Though astronomers have never confirmed a collision between exoplanets in another star system before there is evidence that a similar cosmic crash occurred in our own solar system [Earth and Thea whic   

    From Discover Magazine: “First Evidence of a Giant Exoplanet Collision” 

    DiscoverMag

    From Discover Magazine

    February 18, 2019
    Jake Parks

    1
    A planetary collision is exactly as bad as you would imagine. Unlike an asteroid impact, there’s not just a crater left behind. Instead, such a massive crash causes the surviving world to be stripped of much of its lighter elements, leaving behind an overly dense core. [Thea crashes into Earth] (Credit: NASA/JPL-Caltech)

    For the first time ever, astronomers think they’ve discovered an exoplanet that survived a catastrophic collision with another planet. And according to the new research, which was published Feb. 4, in the journal Nature Astronomy, the evidence for the impact comes from two twin exoplanets that seem to be more fraternal than identical.

    Mass Matters

    The pair of planets in question orbit a Sun-like star (along with two other planets) in the Kepler-107 system, which is located roughly 1,700 light-years away in the constellation Cygnus the Swan.

    Known as Kepler-107b and Kepler-107c, these planets have nearly identical sizes (both have a radius of roughly 1.5 times that of Earth), yet one planet is nearly three times as massive as the other. The innermost planet, Kepler-107b, is about 3.5 times as massive as Earth, while Kepler-107c, which sits farther out, is a whopping 9.4 times as massive as Earth.

    This means the inner planet, Kepler-107b, has an Earth-like density of around 5.3 grams per cubic centimeter, while the more distant Kepler-107c has a density of around 12.6 grams per cubic centimeter — which is extremely dense, even for an alien world. (For reference, water has a density of 1 gram per cubic centimeter.)

    This perplexing density discrepancy left researchers scratching their heads. How could two equally sized exoplanets in the same system (and at nearly the same orbital distance) have such different compositions?

    The Cause

    To determine exactly why Kepler-107c is so dense, first the researchers considered what they already knew. Previous research has shown that intense stellar radiation can strip the atmosphere from a planet that sits too near its host star. But if the innermost planet lost its lighter atmospheric elements, it should be more dense than its twin, not less. According to the study, this would “make the more-irradiated and less-massive planet Kepler-107b denser than Kepler-107c,” which is clearly not the case.

    However, there is another way that a planet can lose a lot of mass: by getting smacked with another planet. And this is exactly what the researchers think happened to Kepler-107c.

    The researchers argue that the denser planet, Kepler-107c, likely experienced a massive collision with a third, unknown planet at some point in its past. Such a gigantic impact, the study says, would have stripped the lighter silicate mantle from Kepler-107c, leaving behind an extremely dense, iron-rich core. According to the study, Kepler-107c could be as much as 70 percent iron.

    Because the mass and radius of Kepler-107c matches what would be expected from a giant planetary impact, the researchers are fairly confident that the collisional scenario they’ve outlined in their paper is accurate; however, they still need to confirm their hypothesis. If proven correct, this new find would become the first-ever evidence of a planetary collision outside our solar system.

    Closer to Home

    Though astronomers have never confirmed a collision between exoplanets in another star system before, there is evidence that a similar cosmic crash occurred in our own solar system. In fact, a leading theory about the formation of the Moon is that it formed when a small protoplanet [Thea, roughly the size of Mars] rammed into early Earth.

    By analyzing lunar samples returned by the Apollo missions, scientists learned that the composition of Moon rocks is very similar to that of Earth’s mantle. Furthermore, the Moon is severely lacking in volatile elements, which boil away at high temperatures. Taken together, along with a few other lines of evidence, this indicates the Moon may have formed when a very large object (roughly the size of Mars) struck Earth with a glancing blow early in the solar system’s history, some 4.6 billion years ago.

    This mash-up melted and tore off some of the outer layers of Earth, which may have temporarily formed Saturn-like rings around our planet. Over time, much of this ejected material drifted back to Earth’s surface, but there was still enough debris left in orbit that it eventually coagulated and formed the Moon.

    With the discovery of Kepler-107c, it seems planet-shattering impacts are not just a sci-fi trope, but instead may occur much more frequently than we once thought. And with the long-anticipated launch of the James Webb Space Telescope coming up in March 2021, it may only be a few more years until they start to reveal themselves en masse, so be sure to stay tuned.

    See the full article here .

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  • richardmitnick 11:25 am on September 5, 2018 Permalink | Reply
    Tags: , , , , Exoplanet research, ,   

    From Many Worlds: “A National Strategy for Finding and Understanding Exoplanets (and Possibly Extraterrestrial Life)” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-09-05
    Marc Kaufman

    1
    The National Academies of Science, Engineering and Medicine took an in-depth look at what NASA, the astronomy community and the nation need to grow the burgeoning science of exoplanets — planets outside our solar system that orbit a star. (NAS)

    An extensive, congressionally-directed study of what NASA needs to effectively learn how exoplanets form and whether some may support life was released today, and it calls for major investments in next-generation space and ground telescopes. It also calls for the adoption of an increasingly multidisciplinary approach for addressing the innumerable questions that remain unanswered.

    While the recommendations were many, the top line calls were for a sophisticated new space-based telescope for the 2030s that could directly image exoplanets, for approval and funding of the long-delayed and debated WFIRST space telescope, and for the National Science Foundation and to help fund two of the very large ground-based telescopes now under development.

    The study of exoplanets has seen remarkable discoveries in the past two decades. But the in-depth study from the private, non-profit National Academies of Sciences, Engineering and Medicine concludes that there is much more that we don’t understand than that we do, that our understandings are “substantially incomplete.”

    So the two overarching goals for future exoplanet science are described as these:

    To understand the formation and evolution of planetary systems as products of star formation and characterize the diversity of their architectures, composition, and environments.
    To learn enough about exoplanets to identify potentially habitable environments and search for scientific evidence of life on worlds orbiting other stars.

    Given the challenge, significance and complexity of these science goals, it’s no wonder that young researchers are flocking to the many fields included in exoplanet science. And reflecting that, it is perhaps no surprise that the NAS survey of key scientific questions, goals, techniques, instruments and opportunities runs over 200 pages. (A webcast of a 1:00 pm NAS talk on the report can be accessed here.)

    2
    Artist’s concept showing a young sun-like star surrounded by a planet-forming disk of gas and dust. (NASA/JPL-Caltech/T. Pyle)

    These ambitious goals and recommendations will now be forwarded to the arm of the National Academies putting together 2020 Astronomy and Astrophysics Decadal Survey — a community-informed blueprint of priorities that NASA usually follows.

    This priority-setting is probably most crucial for the two exoplanet direct imaging missions now being studied as possible Great Observatories for the 2030s — the paradigm-changing space telescopes NASA has launched almost every decade since the 1970s.

    HabEx (the Habitable Exoplanet Observatory) and LUVOIR (the Large UV/Optical/IR Surveyor) are two direct-imaging exoplanet projects in conception phase that would indeed significantly change the exoplanet field.

    NASA Habitable Exoplanet Imaging Mission (HabEx) The Planet Hunter

    NASA Large UV Optical Infrared Surveyor (LUVOIR)

    Both would greatly enhance scientists’ ability to detect and characterize exoplanets. But the more ambitious LUVOIR in particular, would not only find many exoplanets in all stages of formation, but could readily read chemical components of the atmospheres and thereby get clear data on whether the planet was habitable or even if it supported life. The LUVOIR would provide either an 8 meter or a record-breaking 15-meter space telescope, while HabEx would send up a 4 meter mirror.

    HabEx and LUVOIR are competing with two other astrophysics projects for that Great Observatory designation, and so NAS support now and prioritizing later is essential if they are to become a reality.

    3
    An artist notional rendering of an approximately 15-meter telescope in space. This image was created for an earlier large space telescope feasibility project called ATLAST, but it is similar to what is being discussed inside and outside of NASA as a possible great observatory after the James Webb Space Telescope and the Wide-Field Infrared Survey Telescope. (NASA)

    These two potential Great Observatories will be costly and would take many years to design and build. As the study acknowledges and explains, “While the committee recognized that developing a direct imaging capability will require large financial investments and a long time scale to see results, the effort will foster the development of the scientific community and technological capacity to understand myriad worlds.”

    So a lot is at stake. But with budget and space priorities in flux, the fate of even the projects given the highest priority in the Decadal Survey remains unclear.

    That’s apparent in the fact that one of the top recommendations of today’s study is the funding of the number one priority put forward in the 2010 Astronomy and Astrophysics Decadal Survey — the Wide Field Infrared Survey Telescope (WFIRST.)

    NASA/WFIRST

    The project — which would boost the search for exoplanets further from their stars than earlier survey missions– was cancelled in the administration’s proposed 2019 federal budget. Congress has continued funding some development of this once top priority, but its future nonetheless remains in doubt.

    WFIRST could have the capability of directly imaging exoplanets if it were built with technology to block out the blinding light of the star around which exoplanets would be orbiting — doing so either with internal coronagraph or a companion starshade. This would be novel technology for a space-based telescope, and the NAS survey recommends it as well.

    4
    An artist’s rendering of a possible “starshade” that could be launched to work with WFIRST or another space telescope and allow the telescope to take direct pictures of other Earth-like planets. (NASA/JPL-Caltech)

    The list of projects the study recommends is long, with these important additions:

    “Ground-based astronomy – enabled by two U.S.-led telescopes – will also play a pivotal role in studying planet formation and potentially terrestrial worlds, the report says. The future Giant Magellan telescope (GMT) and proposed Thirty Meter Telescope (TMT) would allow profound advances in imaging and spectroscopy – absorption and emission of light – of entire planetary systems.

    Giant Magellan Telescope, to be at the Carnegie Institution for Science’s Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high

    TMT-Thirty Meter Telescope, proposed and now approved for Mauna Kea, Hawaii, USA4,207 m (13,802 ft) above sea level

    They also could detect molecular oxygen in temperate terrestrial planets in transit around close and small stars, the report says.

    The committee pointed out that the technology road map to enable the full potential of GMT and TMT in the study of exoplanets is in need of investments, and should leverage the existing network of U.S. centers and laboratories. To that end, the report recommends that the National Science Foundation invest in both telescopes and their exoplanet instrumentation to provide all-sky access to the U.S. community.”

    And for another variety of ground-based observing the study called for the funding of a project to substantially increase the precision of instruments that find and measure exoplanets using the detected “wobble” of the host star. But stars are active with or without a nearby exoplanet, and so it has been difficult to achieve the precision that astronomers using this “radial velocity” technique need to find and characterize smaller exoplanets.

    Several smaller efforts increase this precision are under way in the U.S., and the European Southern Observatory has a much larger project in development.

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    While the NAS report gives a lot of attention to instruments and ways to use them, it also focuses as never before on astrobiology — the search for life beyond Earth.

    Much work has been done on how to determine whether life exists on a distant planet through modeling and theorizing about biosignatures. The report encourages scientists to expand that work and embraces it as a central aspect of exoplanet science.

    The study also argues that interdisciplinary science — bringing together researchers from many disciplines — is the necessary way forward. It highlights the role of the Nexus for Exoplanet System Science, a NASA initiative which since 2015 has brought together a limited but broad number of science teams from institutions across the country to learn about each other’s work and collaborate whenever possible.

    The initiative itself has not required much funding, instead bringing in teams that had been supported with other grants.

    But now, the NAS study recommends that “building on the NExSS model, NASA should support a cross-divisional exoplanet research coordination network that includes additional membership opportunities via dedicated proposal calls for interdisciplinary research.”

    The initiative, which I’m proud to say sponsors this column, would potentially grow during this process.

    See the full article here .


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    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
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