Tagged: Exoplanet research Toggle Comment Threads | Keyboard Shortcuts

  • 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 .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • 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 .


    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 1:03 pm on August 5, 2018 Permalink | Reply
    Tags: , , , , Exoplanet research, ,   

    From NOVA: “NASA’s TESS Spacecraft Will Scan the Sky For Exoplanets” 

    PBS NOVA

    From NOVA

    13 Apr 2018 [Just now in social media.]
    Allison Eck

    1
    NASA/TESS will identify exoplanets orbiting the brightest stars just outside our solar system.

    The era of big data is here—not just for life on Earth, but in our quest to find Earth-like worlds, too.

    Next Monday, April 16, NASA’s $200-million Transiting Exoplanet Survey Satellite, or TESS, will surge skyward on a SpaceX Falcon 9 rocket. If all goes well, over the next two years, it will search space for signs of exoplanets, or planets beyond our own solar system. So far, scientists have found around 4,000 such celestial bodies freckled across the face of the universe, including seven Earth-sized planets orbiting the dwarf star Trappist-1 about 235 trillion miles away. NASA’s Kepler spacecraft, launched in 2009, has led this revolutionary effort—but now it’s running out of fuel.

    NASA/Kepler Telescope

    TESS, its replacement, will document close-by exoplanets circling bright stars (as opposed to the more distant ones Kepler surveyed). These data points will give scientists more information about the planets ripest for scientific exploration—and which may harbor life.

    “TESS’s job is to find an old-fashioned address book of all the planets spread out around all the stars in the sky,” said Sara Seager, astrophysicist and planetary scientist at MIT and deputy science director for the TESS mission.

    George Ricker, principal investigator for TESS, estimates that the spacecraft will be able to find some 500 super-Earths, or planets that are one-and-a-half to two times the size of Earth, and several dozen Earth-sized planets. Many of these likely orbit red dwarf stars, which are smaller and cooler than our Sun. TESS will watch for transits—the slight dimming of stars as planets pass in front of them from our vantage point on Earth.

    Planet transit. NASA/Ames

    Since red dwarfs are cooler than the Sun, habitable zone planets that revolve around them will orbit closer to their host star, making transits more frequent—and thus more scientifically useful.

    “The transits are a repeating phenomenon. Once you’ve established that a given host star has planets, you can predict where they will be in the future,” Ricker said. “That’s really going to be one of the lasting legacies from TESS.”

    Stephen Rinehart, project scientist for TESS, says that with Kepler, the goal was to get a narrow, deep look at one slice of the cosmos. By contrast, TESS will take an expansive look at the most promising candidates for future research—and compare and contrast them.

    “It’s changing the nature of the dialogue,” Rinehart said. “So far, the nature of our conversations about exoplanets have really been statistical. With TESS, we’ll find planets around bright stars that are well-suited to follow-up observations, where we can talk not just about what the population is like, but we can start talking about what individual planets are like.”

    TESS will gaze upon 20 million stars in the solar neighborhood. Kepler was only able to look at about 200,000. “We’ve got a factor of a hundred more stars that we’re going to be able to look at,” Ricker said. “These are the objects that people are going to want to come back to centuries from now.”

    The spacecraft will act as a bridge to future projects, too, like the James Webb Telescope, which is set to launch in May of 2020. That telescope will study every phase in the history of our universe—and it’ll act as the “premier observatory of the next decade.”

    Our history with exoplanets is surprisingly brief. While we had dreamt of them for centuries, it was only 25 years ago that we confirmed their existence. Now, we know that nearly every red dwarf in the Milky Way has a family of planets, and that maybe 20% of those planets lie with the habitable zone. With so much variety and many to choose from, scientists hope that by studying their atmospheres, they’ll be able to detect signs of life.

    “[Habitability] is one of the philosophical questions of our time,” Rinehart said. “Can we find evidence that there’s even a possibility of other life nearby us in the universe? TESS isn’t going to quite get us there. TESS is an important step forward.”

    Paul Hertz, director of astrophysics for NASA, echoes Rinehart’s optimism.

    “After TESS is done, you’ll be able to go outside at night, take your grandchild by the hand, and point to a star and say, ‘I know there’s a planet around that star. Let’s talk about what that planet might be like,’” Hertz said. “Nobody’s ever been able to do that in the history of mankind.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

     
  • richardmitnick 1:50 pm on May 13, 2018 Permalink | Reply
    Tags: , , , , , , Exoplanet research, , ,   

    From ASU via Science News: “The recipes for solar system formation are getting a rewrite” 

    ASU Bloc

    From Arizona State University


    Science News

    May 11, 2018
    Lisa Grossman

    Exoplanets: Left to right Kepler-22b, Kepler-69c, Kepler-62e, Kepler-62f, with Earth-except for Earth these are artists’ concepts. Image credit: NASA Ames/ JPL-Caltech

    With a mortar and pestle, Christy Till blends together the makings of a distant planet. In her geology lab at Arizona State University in Tempe, Till carefully measures out powdered minerals, tips them into a metal capsule and bakes them in a high-pressure furnace that can reach close to 35,000 times Earth’s atmospheric pressure and 2,000° Celsius.

    In this interplanetary test kitchen, Till and colleagues are figuring out what might go into a planet outside of our solar system.

    “We’re mixing together high-purity powders of silica and iron and magnesium in the right proportions to make the composition we want to study,” Till says. She’s starting with the makings of what might resemble a rocky planet that’s much different from Earth. “We literally make a recipe.”

    Scientists have a few good ideas for how to concoct our own solar system. One method: Mix up a cloud of hydrogen and helium, season generously with oxygen and carbon, and sprinkle lightly with magnesium, iron and silicon. Condense and spin until the cloud forms a star surrounded by a disk. Let rest about 10 million years, until a few large lumps appear. After about 600 million years, shake gently.

    1
    GET COOKING Geologist Christy Till mixes up a mock exoplanet from powdered minerals in her Arizona lab. Abigail Weibel Photography

    But that’s only one recipe in the solar systems cookbook. Many of the planets orbiting other stars are wildly different from anything seen close to home. As the number of known exoplanets has climbed — 3,717 confirmed as of April 12 — scientists are creating new recipes.

    Seven of those exoplanets are in the TRAPPIST-1 system, one of the most exciting families of planets astronomers have discovered to date.

    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


    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

    At least three TRAPPIST-1 planets might host liquid water on their surface, making them top spots to look for signs of life (SN: 12/23/17, p. 25).

    Yet those planets shouldn’t exist. Astronomers calculated that the small star’s preplanet disk shouldn’t have contained enough rocky material to make even one Earth-sized orb, says astrophysicist Elisa Quintana of NASA’s Goddard Space Flight Center in Greenbelt, Md. Yet the disk whipped up seven.

    TRAPPIST-1 is just one of the latest in a long line of rule breakers.
    Other systems host odd characters not seen in our solar system: super-Earths, mini-Neptunes, hot Jupiters and more. Many exoplanets must have had chaotic beginnings to exist where we find them.

    These oddballs raise exciting questions about how solar systems form. Scientists want to know how much of a planet’s ultimate fate depends on its parent star, which ingredients are essential for planet building and which are just frosting on the planetary cake.

    NASA’s Transiting Exoplanet Survey Satellite, or TESS, which launched April 18, should bring in some answers.

    NASA/TESS

    TESS is expected to find thousands more exoplanets in the next two years. That crowd will help illuminate which planetary processes are the most common — and will help scientists zero in on the best planets to check for signs of life.


    CAKE POP PLANETS Yes, baking actually makes a nice analogy for planet formation. Take a look.

    Beyond the bare necessities

    All solar system recipes share some basic elements. The star and its planets form from the same cloud of gas and dust. The densest region of the cloud collapses to form the star, and the remaining material spreads itself into a rotating disk, parts of which will eventually coalesce into planets. That similarity between the star and its progeny tells Till and other scientists what to toss into the planetary stand mixer.

    “If you know the composition of the star, you can know the composition of the planets,” says astronomer Johanna Teske of the Carnegie Observatories in Pasadena, Calif. A star’s composition is revealed in the wavelengths of light the star emits and absorbs.

    When a planet is born can affect its final makeup, too. A gas giant like Jupiter first needs a rocky core about 10 times Earth’s mass before it can begin gobbling up gas. That much growth probably happens well before the disk’s gas disappears, around 10 million years after the star forms. Small, rocky planets like Earth probably form later.

    Finally, location matters. Close to the hot star, most elements are gas, which is no help for building planets from scratch. Where the disk cools toward its outer edge, more elements freeze to solid crystals or condense onto dust grains. The boundary where water freezes is called the snow line. Scientists thought that water-rich planets must either form beyond their star’s snow line, where water is abundant, or must have water delivered to them later (SN: 5/16/15, p. 8). Giant planets are also thought to form beyond the snow line, where there’s more material available.

    But the material in the disk might not stay where it began, Teske says. “There’s a lot of transport of material, both toward and away from the star,” she says. “Where that material ends up is going to impact whether it goes into planets and what types of planets form.” The amount of mixing and turbulence in the disk could contribute to which page of the cookbook astronomers turn to: Is this system making a rocky terrestrial planet, a relatively small but gaseous Neptune or a massive Jupiter?

    _________________________________________________________________
    Birthplace

    In the disk around a star, giant planets form beyond the “snow line,” where water freezes and more solids are available. Turbulence closer in knocks things around.
    3

    Source: T. Henning and D. Semenov/Chemical Reviews 2013
    _________________________________________________________________

    Some like it hot

    Like that roiling disk material, a full-grown planet can also travel far from where it formed.

    Consider “Hoptunes” (or hot Neptunes), a new class of planets first named in December in Proceedings of the National Academy of Sciences. Hoptunes are between two and six times Earth’s size (as measured by the planet’s radius) and sidled up close to their stars, orbiting in less than 10 days. That close in, there shouldn’t have been enough rocky material in the disk to form such big planets. The star’s heat should mean no solids, just gases.

    Hoptunes share certain characteristics — and unanswered questions — with hot Jupiters, the first type of exoplanet discovered, in the mid-1990s.

    “Because we’ve known about hot Jupiters for so long, some people kind of think they’re old hat,” says astronomer Rebekah Dawson of Penn State, who coauthored a review about hot Jupiters posted in January at arXiv.org. “But we still by no means have a consensus about how they got so close to their star.”

    Since the first known hot Jupiter, 51 Pegasi b, was confirmed in 1995, two explanations for that proximity have emerged. A Jupiter that formed past the star’s snow line could migrate in smoothly through the disk by trading orbital positions with the disk material itself in a sort of gravitational do-si-do. Or interactions with other planets or a nearby star could knock the planet onto an extremely elliptical or even backward orbit (SN Online: 11/1/13). Over time, the star’s gravity would steal energy from the orbit, shrinking it into a tight, close circle. Dawson thinks both processes probably happen.

    Hot Jupiters are more common around stars that contain a lot of elements heavier than hydrogen and helium, which astronomers call metals, astronomer Erik Petigura of Caltech and colleagues reported in February in The Astronomical Journal. High-metal stars probably form more planets because their disks have more solids to work with. Once a Jupiter-sized planet forms, a game of gravitational billiards could send it onto an eccentric orbit — and send smaller worlds out into space. That fits the data, too; hot Jupiters tend to lack companion worlds.

    Hoptunes follow the same pattern: They prefer metal-rich stars and have few sibling planets. But Hoptunes probably arrived at their hot orbits later in the star’s life. Getting close to a young star, a Hoptune would risk having its atmosphere stripped away. “They’re sort of in the danger zone,” Dawson says. Since Hoptunes do, in fact, have atmospheres, they were probably knocked onto an elliptical, and eventually close-in, orbit later.

    One striking exception to the hot loner rule is WASP-47b, [ApJL] a hot Jupiter with two nearby siblings between the sizes of Earth and Neptune. That planet is one reason Dawson thinks there’s more than one way to cook up a hot Jupiter.

    Rock or gas

    Hot Jupiters are so large that astronomers assume these exoplanets have thick atmospheres. But it’s harder to tell if a smaller planet is gassy like Neptune or rocky like Earth.

    To make a first guess at a planet’s composition, astronomers need to know the planet’s size and mass. Together, those numbers yield the planet’s density, which gives a sense of how much of the planet is solid like rock or diffuse like an atmosphere.

    3
    HOME SWEET HOMES New images from the Very Large Telescope in Chile reveal that dust disks around young stars can take on many different forms. The shape of a disk can affect – and be affected by – the presence of baby planets.

    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)


    ESO/H. Avenhaus et al./E. Sissa et al./DARTT-S and SHINE collaborations

    The most popular planet detection strategies each measure one of those factors. The transit method, used by the Kepler space telescope, watches a star wink as the planet passes in front.

    NASA/Kepler Telescope

    Planet transit. NASA/Ames

    Comparing the star’s light before and during the transit reveals the planet’s size. The radial velocity method, used with telescopes on the ground, watches the star wobble in response to a planet’s gravity, which reveals the planet’s mass.

    Radial velocity Image via SuperWasp http http://www.superwasp.org-exoplanets.htm


    Radial Velocity Method-Las Cumbres Observatory

    [Left out of the discussion, Direct Imaging.

    Direct imaging-This false-color composite image traces the motion of the planet Fomalhaut b, a world captured by direct imaging.

    To me, this is a lapse in journalistic coverage as Direct Imaging is becomeing ao more powerful tool with new telescope capabilities.]

    Most of the stars observed by Kepler are too far away and too dim for direct, accurate measures of planet masses. But astronomers have inferred a size cutoff for rocky planets. Last June, researchers analyzing the full Kepler dataset noticed a surprising lack of planets between 1.5 and two times Earth’s size and suggested those 1.5 times Earth’s radius or smaller are probably rocky; two to 3.5 times Earth’s radius are probably gassy (SN Online: 6/19/17).

    Dozens more planets have had their masses inferred indirectly, mostly those in multiplanet systems where astronomers can observe how planets tug on one another. From what astronomers can tell, super-Earths — planets between one and about 10 times Earth’s mass — come in a wide range of compositions.

    The Kepler mission is about to end, as the spacecraft’s fuel is running out. TESS will pick up where Kepler leaves off. The new planet-hunting space telescope will revolutionize the study of super-Earth densities. It will scan 85 percent of the sky for bright, nearby stars to pick out the best planets for follow-up study. As part of its primary mission, TESS will find at least 50 planets smaller than Neptune that can have their masses measured precisely, too. “Having masses … will help us understand the compositions,” says Quintana, a TESS team member. “We can see: Is there a true transition line where planets go rocky to gaseous? Or is it totally random? Or does it depend on the star?”

    Star power

    All kinds of planets’ fates do, in fact, depend on the stars, Petigura’s recent work suggests. In a February report in The Astronomical Journal, he and colleagues measured the metal contents of 1,305 planet-hosting stars in Kepler’s field of view.

    The researchers learned that large planets and close-in planets — with orbital periods of 10 days or less — are more common around metal-rich stars. But the team was surprised to find that small planets and planets that orbit far from their stars show up around stars of all sorts of compositions. “They form efficiently everywhere,” Petigura says.

    That could mean that metal-rich stars had disks that extended closer to the stars. With enough material close to the star, hot super-Earths could have formed where they currently spin. The existence of hot super-Earths might even suggest that hot Jupiters can form close to the star after all. A super-Earth or mini-Neptune could represent the core of what was once a hot Jupiter that didn’t quite gather enough gas before the disk dissipated, or whose atmosphere was blown off by the star (SN Online: 10/31/17).

    Weird water

    Some scientists are looking to stars to reveal what’s inside a planet. The help is welcome because density is a crude measure for understanding what a planet is made of. Planets with the same mass and radius can have very different compositions and natures — look at hellish Venus and livable Earth.

    Take the case of TRAPPIST-1, which has seven Earth-sized worlds and is 39 light-years away. Astronomers are anxious to check at least three of the planets for signs of life
    (SN: 12/23/17, p. 25). But those planets might be so waterlogged that any signs of life would be hard to detect, says exogeologist Cayman Unterborn of Arizona State. So much water would change a planet’s chemistry in a way that makes it hard to tell life from nonlife. Based on the planets’ radii (measured by their transits) and their masses (measured by their gravitational influence on one another), Unterborn and colleagues used density to calculate a bizarre set of interiors for the worlds, which the team reported March 19 in Nature Astronomy.

    The TRAPPIST-1 planets have low densities for their size, Unterborn says, suggesting that their masses are mostly light material like water ice. TRAPPIST-1b, the innermost planet, seems to be 15 percent water by mass (Earth is less than 0.1 percent water). The fifth planet out, TRAPPIST-1f, may be at least half water by mass. If the planet formed with all that water already in it, it would have had 1,000 Earth oceans’ worth of water. That amount of water would compress into exotic phases of ice not found at normal pressures on Earth. “That is so much water that the chemistry of how that planet crystallized is not something we have ever imagined,” Unterborn says.

    _______________________________________________________
    Size it up

    Measuring a planet’s mass and radius gives astronomers a sense of planetary makeup. This plot compares the TRAPPIST-1 planets (purple) with Earth, Venus, an exoplanet named K2-229b and a couple of other worlds.

    5

    Source: A. Santerne et al/Nature Astronomy 2018

    _______________________________________________________

    But there’s a glitch. Unterborn’s analysis was based on the most accurate published masses for the TRAPPIST-1 worlds at the time. But on February 5, the same day his paper was accepted in Nature Astronomy, a group led by astronomer Simon Grimm of the University of Bern in Switzerland posted more precise mass measurements at Astronomy and Astrophysics. Those masses make the soggiest planets look merely damp.

    Clearly, Unterborn says, density is not destiny. Studying a planet based on its mass and radius has its limits.

    Looking deeper

    As a next step, Unterborn and colleagues have published a series of papers suggesting how stellar compositions can tell the likelihood that a group of planets have plate tectonics, or how much oxygen the planet atmospheres may have. Better geologic models may ultimately help reveal if a single planet is habitable.

    But Unterborn is wary of translating composition from a star to any individual planet — existing geochemical models aren’t good enough. The recent case of K2-229b makes that clear. Astronomer Alexandre Santerne of the Laboratory of Astrophysics of Marseille in France and colleagues recently tried to see if a star’s composition could describe the interior of its newly discovered exoplanet, K2-229b. The team reported online March 26 in Nature Astronomy that the planet has a size similar to Earth’s but a makeup more like Mercury’s: 70 percent metallic core, 30 percent silicate mantle by mass. (The researchers nicknamed the planet Freddy, for Queen front man Freddie Mercury, Santerne wrote on Twitter.) That composition is not what they’d expect from the star alone.

    __________________________________________________
    Hints from the star

    Based on its mass and radius, an exoplanet named K2-229b is about Earth’s size but more similar to Mercury in composition, astronomers suggest.

    6

    Source: A. Santerne et al/Nature Astronomy 2018

    __________________________________________________

    Geologic models need to catch up quickly. After TESS finds the best worlds for follow-up observations, the James Webb Space Telescope, due to launch in 2020, will search some of those planets’ atmospheres for signs of life (SN: 4/30/16, p. 32). For that strategy to work, Unterborn says, scientists need a better read on the exoplanet cookbook.

    Christy Till’s pressure-packed test kitchen may help. Till is primarily a volcanologist who studies how magma erupting onto Earth’s surface can reveal conditions in Earth’s interior. “The goal is to start doing that for exoplanets,” she says.

    Till and colleagues are redoing some foundational experiments conducted for Earth 50 years ago but not yet done for exoplanets. The experiments predict which elements can go into planets’ mantles and cores, and which will form solid crusts. (Early results that Till presented in December in New Orleans at the American Geophysical Union meeting suggest that multiplying the sun’s magnesium-to-silicon ratio by 1.33 still bakes a rocky planet, but with a different flavored crust than Earth’s.)

    Till uses three piston cylinders to squash and singe synthetic exoplanets for 24 hours to see what minerals form and melt at different pressures and temperatures. The results may help answer questions like what kind of lava would erupt on a planet’s surface, what would the crust be made of and what gases might end up in the planet’s atmosphere.

    It’s early days, but Till’s recipe testing may mean scientists won’t have to wait decades for telescopes to get a close enough look at an exoplanet to judge how much like home it really is. With new cookbook chapters, Unterborn says, “we can figure out which stars are the best places to build an Earth.”

    Related journal articles
    _________________________________________________
    See the full article for further references with links.

    See the full article here .

    Please help promote STEM in your local schools.

    stem

    Stem Education Coalition

    ASU is the largest public university by enrollment in the United States.[11] Founded in 1885 as the Territorial Normal School at Tempe, the school underwent a series of changes in name and curriculum. In 1945 it was placed under control of the Arizona Board of Regents and was renamed Arizona State College.[12][13][14] A 1958 statewide ballot measure gave the university its present name.
    ASU is classified as a research university with very high research activity (RU/VH) by the Carnegie Classification of Institutions of Higher Education, one of 78 U.S. public universities with that designation. Since 2005 ASU has been ranked among the Top 50 research universities, public and private, in the U.S. based on research output, innovation, development, research expenditures, number of awarded patents and awarded research grant proposals. The Center for Measuring University Performance currently ranks ASU 31st among top U.S. public research universities.[15]

    ASU awards bachelor’s, master’s and doctoral degrees in 16 colleges and schools on five locations: the original Tempe campus, the West campus in northwest Phoenix, the Polytechnic campus in eastern Mesa, the Downtown Phoenix campus and the Colleges at Lake Havasu City. ASU’s “Online campus” offers 41 undergraduate degrees, 37 graduate degrees and 14 graduate or undergraduate certificates, earning ASU a Top 10 rating for Best Online Programs.[16] ASU also offers international academic program partnerships in Mexico, Europe and China. ASU is accredited as a single institution by The Higher Learning Commission.

    ASU Tempe Campus
    ASU Tempe Campus

     
  • richardmitnick 7:42 am on March 21, 2018 Permalink | Reply
    Tags: , , , , , , Exoplanet research   

    From ESA: “ESA’s Next Science Mission To Focus on Nature of Exoplanet” 

    ESA Space For Europe Banner

    European Space Agency

    20 March 2018

    Markus Bauer








    ESA Science Communication Officer









    Tel: +31 71 565 6799









    Mob: +31 61 594 3 954









    Email: markus.bauer@esa.int

    1
    Hot exoplanet.

    The nature of planets orbiting stars in other systems will be the focus for ESA’s fourth medium-class science mission, to be launched in mid 2028.

    Ariel, the Atmospheric Remote‐sensing Infrared Exoplanet Large‐survey mission, was selected by ESA today as part of its Cosmic Vision plan.

    1
    ESA Ariel spacecraft.

    The mission addresses one of the key themes of Cosmic Vision: What are the conditions for planet formation and the emergence of life?

    Thousands of exoplanets have already been discovered with a huge range of masses, sizes and orbits, but there is no apparent pattern linking these characteristics to the nature of the parent star. In particular, there is a gap in our knowledge of how the planet’s chemistry is linked to the environment where it formed, or whether the type of host star drives the physics and chemistry of the planet’s evolution.

    Ariel will address fundamental questions on what exoplanets are made of and how planetary systems form and evolve by investigating the atmospheres of hundreds of planets orbiting different types of stars, enabling the diversity of properties of both individual planets as well as within populations to be assessed.

    Observations of these worlds will give insights into the early stages of planetary and atmospheric formation, and their subsequent evolution, in turn contributing to put our own Solar System in context.

    “Ariel is a logical next step in exoplanet science, allowing us to progress on key science questions regarding their formation and evolution, while also helping us to understand Earth’s place in the Universe,” says Günther Hasinger, ESA Director of Science.

    “Ariel will allow European scientists to maintain competitiveness in this dynamic field. It will build on the experiences and knowledge gained from previous exoplanet missions.”

    The mission will focus on warm and hot planets, ranging from super-Earths to gas giants orbiting close to their parent stars, taking advantage of their well-mixed atmospheres to decipher their bulk composition.

    Ariel will measure the chemical fingerprints of the atmospheres as the planet crosses in front of its host star, observing the amount of dimming at a precision level of 10–100 parts per million relative to the star.

    As well as detecting signs of well-known ingredients such as water vapour, carbon dioxide and methane, it will also be able to measure more exotic metallic compounds, putting the planet in context of the chemical environment of the host star.

    For a select number of planets, Ariel will also perform a deep survey of their cloud systems and study seasonal and daily atmospheric variations.

    Ariel’s metre-class telescope will operate at visible and infrared wavelengths. It will be launched on ESA’s new Ariane 6 rocket from Europe’s spaceport in Kourou in mid 2028. It will operate from an orbit around the second Lagrange point, L2, 1.5 million kilometres directly ‘behind’ Earth as viewed from the Sun, on an initial four-year mission.

    Following its selection by ESA’s Science Programme Committee, the mission will continue into another round of detailed mission study to define the satellite’s design. This would lead to the ‘adoption’ of the mission – presently planned for 2020 – following which an industrial contractor will be selected to build it.

    Ariel was chosen from three candidates, competing against the space plasma physics mission Thor (Turbulence Heating ObserveR) and the high-energy astrophysics mission Xipe (X-ray Imaging Polarimetry Explorer).

    Solar Orbiter, Euclid and Plato have already been selected as medium-class missions.

    NASA/ESA Solar Orbiter

    ESA/Euclid spacecraft

    ESA/PLATO

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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.

    ESA50 Logo large

     
  • richardmitnick 1:13 pm on December 20, 2017 Permalink | Reply
    Tags: , , , , Exoplanet research, Habitable planets could exist around pulsars, , , The first exoplanets ever discovered were around the pulsar PSR B1257+12,   

    From U Cambridge: “Habitable planets could exist around pulsars” 

    U Cambridge bloc

    University of Cambridge

    19 Dec 2017
    Sarah Collins
    sarah.collins@admin.cam.ac.uk

    1
    It is theoretically possible that habitable planets exist around pulsars – spinning neutron stars that emit short, quick pulses of radiation. According to new research, such planets must have an enormous atmosphere that converts the deadly x-rays and high energy particles of the pulsar into heat. The results, from astronomers at the University of Cambridge and Leiden University, are reported in the journal Astronomy & Astrophysics.

    Pulsars are known for their extreme conditions. Each is a fast-spinning neutron star – the collapsed core of a massive star that has gone supernova at the end of its life. Only 10 to 30 kilometres across, a pulsar possesses enormous magnetic fields, accretes matter, and regularly gives out large bursts of X-rays and highly energetic particles.

    Surprisingly, despite this hostile environment, neutron stars are known to host exoplanets. The first exoplanets ever discovered were around the pulsar PSR B1257+12 – but whether these planets were originally in orbit around the precursor massive star and survived the supernova explosion, or formed in the system later remains an open question. Such planets would receive little visible light but would be continually blasted by the energetic radiation and stellar wind from the host. Could such planets ever host life?

    For the first time, astronomers have tried to calculate the ‘habitable’ zones near neutron stars – the range of orbits around a star where a planetary surface could possibly support water in a liquid form. Their calculations show that the habitable zone around a neutron star can be as large as the distance from our Earth to our Sun. An important premise is that the planet must be a super-Earth, with a mass between one and ten times our Earth. A smaller planet will lose its atmosphere within a few thousand years under the onslaught of the pulsar winds. To survive this barrage, a planet’s atmosphere must be a million times thicker than ours – the conditions on a pulsar planet surface might resemble those of the deep ocean floor on Earth.

    The astronomers studied the pulsar PSR B1257+12 about 2300 light-years away as a test case, using the X-ray Chandra space telescope.

    NASA/Chandra Telescope

    Of the three planets in orbit around the pulsar, two are super-Earths with a mass of four to five times our Earth, and orbit close enough to the pulsar to warm up. According to co-author Alessandro Patruno from Leiden University, “The temperature of the planets might be suitable for the presence of liquid water on their surface. Though, we don’t know yet if the two super-Earths have the right, extremely dense atmosphere.”

    In the future, Patruno and his co-author Mihkel Kama from Cambridge’s Institute of Astronomy would like to observe the pulsar in more detail and compare it with other pulsars. The European Southern Observatory’s ALMA Telescope would be able to show dust discs around neutron stars, which are good predictors of planets. The Milky Way contains about one billion neutron stars, of which about 200,000 are pulsars. So far, 3000 pulsars have been studied and only five pulsar planets have been found.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 1:24 pm on December 14, 2017 Permalink | Reply
    Tags: , , , , Exoplanet research, Kepler-90 system, Kepler-90i – a sizzling hot rocky planet that orbits its star once every 14.4 days   

    From NASA Kepler: “Artificial Intelligence, NASA Data Used to Discover Eighth Planet Circling Distant Star” 

    NASA Kepler Logo

    NASA Kepler Telescope
    NASA/Kepler

    12.14.17

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

    Alison Hawkes
    Ames Research Center, California’s Silicon Valley
    650-604-0281
    alison.j.hawkesbak@nasa.gov

    1
    With the discovery of an eighth planet, the Kepler-90 system is the first to tie with our solar system in number of planets.
    Credits: NASA/Wendy Stenzel

    Our solar system now is tied for most number of planets around a single star, with the recent discovery of an eighth planet circling Kepler-90, a Sun-like star 2,545 light years from Earth. The planet was discovered in data from NASA’s Kepler Space Telescope.

    The newly-discovered Kepler-90i – a sizzling hot, rocky planet that orbits its star once every 14.4 days – was found using machine learning from Google. Machine learning is an approach to artificial intelligence in which computers “learn.” In this case, computers learned to identify planets by finding in Kepler data instances where the telescope recorded signals from planets beyond our solar system, known as exoplanets.

    NASA will host a Reddit Ask Me Anything at 3 p.m. EST today on this discovery.


    Our solar system now is tied for most number of planets around a single star, with the recent discovery of an eighth planet circling Kepler-90, a Sun-like star 2,545 light years from Earth. The planet was discovered in data from NASA’s Kepler Space Telescope.
    Credits: NASA

    “Just as we expected, there are exciting discoveries lurking in our archived Kepler data, waiting for the right tool or technology to unearth them,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington. “This finding shows that our data will be a treasure trove available to innovative researchers for years to come.”

    The discovery came about after researchers Christopher Shallue and Andrew Vanderburg trained a computer to learn how to identify exoplanets in the light readings recorded by Kepler – the miniscule change in brightness captured when a planet passed in front of, or transited, a star. Inspired by the way neurons connect in the human brain, this artificial “neural network” sifted through Kepler data and found weak transit signals from a previously-missed eighth planet orbiting Kepler-90, in the constellation Draco.

    While machine learning has previously been used in searches of the Kepler database, this research demonstrates that neural networks are a promising tool in finding some of the weakest signals of distant worlds.

    Other planetary systems probably hold more promise for life than Kepler-90. About 30 percent larger than Earth, Kepler-90i is so close to its star that its average surface temperature is believed to exceed 800 degrees Fahrenheit, on par with Mercury. Its outermost planet, Kepler-90h, orbits at a similar distance to its star as Earth does to the Sun.

    “The Kepler-90 star system is like a mini version of our solar system. You have small planets inside and big planets outside, but everything is scrunched in much closer,” said Vanderburg, a NASA Sagan Postdoctoral Fellow and astronomer at the University of Texas at Austin.

    Shallue, a senior software engineer with Google’s research team Google AI, came up with the idea to apply a neural network to Kepler data. He became interested in exoplanet discovery after learning that astronomy, like other branches of science, is rapidly being inundated with data as the technology for data collection from space advances.

    “In my spare time, I started googling for ‘finding exoplanets with large data sets’ and found out about the Kepler mission and the huge data set available,” said Shallue. “Machine learning really shines in situations where there is so much data that humans can’t search it for themselves.”

    Kepler’s four-year dataset consists of 35,000 possible planetary signals. Automated tests, and sometimes human eyes, are used to verify the most promising signals in the data. However, the weakest signals often are missed using these methods. Shallue and Vanderburg thought there could be more interesting exoplanet discoveries faintly lurking in the data.

    First, they trained the neural network to identify transiting exoplanets using a set of 15,000 previously-vetted signals from the Kepler exoplanet catalogue. In the test set, the neural network correctly identified true planets and false positives 96 percent of the time. Then, with the neural network having “learned” to detect the pattern of a transiting exoplanet, the researchers directed their model to search for weaker signals in 670 star systems that already had multiple known planets. Their assumption was that multiple-planet systems would be the best places to look for more exoplanets.

    “We got lots of false positives of planets, but also potentially more real planets,” said Vanderburg. “It’s like sifting through rocks to find jewels. If you have a finer sieve then you will catch more rocks but you might catch more jewels, as well.”

    Kepler-90i wasn’t the only jewel this neural network sifted out. In the Kepler-80 system, they found a sixth planet. This one, the Earth-sized Kepler-80g, and four of its neighboring planets form what is called a resonant chain – where planets are locked by their mutual gravity in a rhythmic orbital dance. The result is an extremely stable system, similar to the seven planets in the TRAPPIST-1 system.

    Their research paper reporting these findings has been accepted for publication in The Astronomical Journal. Shallue and Vanderburg plan to apply their neural network to Kepler’s full set of more than 150,000 stars.

    Kepler has produced an unprecedented data set for exoplanet hunting. After gazing at one patch of space for four years, the spacecraft now is operating on an extended mission and switches its field of view every 80 days.

    “These results demonstrate the enduring value of Kepler’s mission,” said Jessie Dotson, Kepler’s project scientist at NASA’s Ames Research Center in California’s Silicon Valley. “New ways of looking at the data – such as this early-stage research to apply machine learning algorithms – promises to continue to yield significant advances in our understanding of planetary systems around other stars. I’m sure there are more firsts in the data waiting for people to find them.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Ames Research Center manages the Kepler and K2 missions for NASA’s Science Mission Directorate. NASA’s Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

    In October 2009, oversight of the Kepler project was transferred from the Discovery Program at NASA’s Marshall Space Flight Center, Huntsville, AL, to the Exoplanet Exploration Program at JPL

    The loss of a second of the four reaction wheels on board the Kepler spacecraft in May 2013 brought an end to Kepler’s four plus year science mission to continuously monitor more than 150,000 stars to search for transiting exoplanets. Developed over the months following this failure, the K2 mission represents a new concept for spacecraft operations that enables continued scientific observations with the Kepler space telescope. K2 became fully operational in June 2014 and is expected to continue operating until 2017 or 2018.

    NASA image

    NASA JPL Icon

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: