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  • richardmitnick 12:05 pm on August 18, 2019 Permalink | Reply
    Tags: , , , , , Exoplanets, , ,   

    From Ethan Siegel: “Ask Ethan: What Has TESS Accomplished In Its First Year Of Science Operations?” 

    From Ethan Siegel
    Aug 17, 2019

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    An illustration of NASA’s TESS satellite and its capabilities of imaging transiting exoplanets. Kepler has given us more exoplanets than any other mission, and it revealed them all through the transit method.

    Planet transit. NASA/Ames

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

    With TESS, we are looking to extend our capabilities even farther, using the same method with superior equipment and techniques. (NASA)

    After Kepler but before James Webb, TESS is preparing astronomers for the coming exoplanet revolution.

    There are always new discoveries and achievements occurring in science, and certain fields have experienced recent advances that are nothing short of revolutionary. A generation ago, humanity didn’t know if stars beyond our Sun had planets around them; today, we’ve discovered thousands of star systems with planets orbiting them. Planets of varying masses orbit all types of star at a vast range of distances, and astronomers are preparing for the day where we can image Earth-sized exoplanets directly to seek signs of extraterrestrial life. Today, in a post-Kepler but pre-James Webb world, TESS is the leading exoplanet-finding mission. A year into its mission, what has it accomplished? That’s what Patreon supporter Tim Graham wants to know, asking:

    With TESS completing [the] first year of its mission, surveying the southern sky, how does it compare to Kepler?

    TESS is fundamentally different than Kepler, but what it’s found should give us all incredible hope for the 2020s.

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    Kepler was designed to look for planetary transits, where a large planet orbiting a star could block a tiny fraction of its light, reducing its brightness by ‘up to’ 1%. The smaller a world is relative to its parent star, the more transits you need to build up a robust signal, and the longer its orbital period, the longer you need to observe to get a detection signal that rises above the noise. Kepler successfully accomplished this for thousands of planets around stars beyond our own. (MATT OF THE ZOONIVERSE/PLANET HUNTERS TEAM)

    There are some similarities between TESS and Kepler in how both missions work.

    Both TESS and Kepler measure the light coming from a target star (or a set of target stars),
    they monitor the total light output over relatively long periods of time,
    they search for periodic dips in the overall flux from the star,
    and if the dips repeat in frequency and magnitude, both extract the radius and orbital distance for a potential candidate planet.

    This is the essence of the transit method in searching for exoplanetary candidates, and it was famously employed by Kepler over its recently-ended mission, beginning in 2009. Thanks largely to Kepler, the number of known exoplanets skyrocketed from a few dozen to many thousands in under a decade.

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    Today, we know of over 4,000 confirmed exoplanets, with more than 2,500 of those found in the Kepler data. These planets range in size from larger than Jupiter to smaller than Earth. Yet because of the limitations on the size of Kepler and the duration of the mission, the majority of planets are very hot and close to their star, at small angular separations. TESS has the same issue with the first planets it’s discovering: they’re preferentially hot and in close orbits. Only through dedicates, long-period observations (or direct imaging) will we be able to detect planets with longer period (i.e., multi-year) orbits. (NASA/AMES RESEARCH CENTER/JESSIE DOTSON AND WENDY STENZEL; MISSING EARTH-LIKE WORLDS BY E. SIEGEL)

    The primary mission of Kepler, however, was fundamentally different from the primary mission of TESS. While Kepler’s goal was to characterize the planetary systems of as many stars as possible in as great detail as possible, TESS is particularly concerned with finding and characterizing exoplanetary systems around the closest stars to Earth. Both of these ambitions are scientifically useful and important, but what TESS is doing doesn’t compare to Kepler at all.

    In order to accomplish the goal, Kepler’s primary mission involved the continuous observation of a small region of the sky, along one of the Milky Way’s spiral arms. These observations spanned three years, encapsulating over 100,000 stars located up to some 3,000 light-years away. Thousands of these stars were discovered to exhibit these transits: the same number you’d expect if every star possessed planets that were randomly aligned relative to our line-of-sight.

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    Kepler’s field-of-view contains approximately 150,000 stars, but transits have only been observed for a few thousand. In theory, nearly all of these stars should have planets, but only a small percentage of planetary systems should have good enough alignments from our perspective for a transit to be observed. (PAINTING BY JON LOMBERG, KEPLER MISSION DIAGRAM ADDED BY NASA)

    Once its primary mission ended [Kepler’s reaction wheels had failed], however, Kepler switched to an alternate goal: the K2 mission. Instead of pointing at one region of the sky for a long period of time, Kepler would observe a different region of the sky for approximately 30 days, search for transits there, and then move on to another region of sky. This led to some incredible discoveries, particularly around the smallest, coolest stars in the Universe: the M-class red dwarfs.

    The lowest-mass stars are also the smallest in physical size, meaning that even a terrestrial-like, rocky planet can block a significant fraction of the star’s light during a transit: enough to have its flux dip detected by Kepler. In addition, these exoplanets can possess very short periods, meaning that to have Earth-like temperatures on them, they’ll need to be so close that they complete a full orbit in less than a month. Many fascinating systems have been discovered and/or measured precisely by the K2 mission.

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    This image montage shows the Maunakea Observatories, the Kepler Space Telescope, and the night sky with various K2 fields-of-view highlighted. Inside each field-of-view there are dots inside, which point out the various planetary systems discovered and measured by the K2 mission. (KAREN TERAMURA (UHIFA); NASA/KEPLER; MILOSLAV DRUCKMÜLLER AND SHADIA HABBAL)

    The K2 mission, perhaps, could be viewed as the best testing ground for TESS, but is still fundamentally different. The Kepler telescope was designed to have a narrow field-of-view but to go relatively deep: measuring flux dips around stars up to thousands of light-years away.

    TESS, on the other hand, was designed to survey practically the entire sky, with a much wider field-of-view. It doesn’t need to go as deep, because its goal is to seek planets around the closest stars to Earth: those within just 200 light-years of us. If there’s a planet orbiting a star with the right orientation to exhibit a transit as viewed from our perspective, TESS will not only find it, but will enable scientists to determine the planet’s orbital distance and physical radius.

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    NASA’s TESS satellite will survey the entire sky in 16 chunks-at-a-time that are approximately 12 degrees across apiece, ranging from the galactic poles down to near the galactic equator. As a result of this surveying strategy, the polar regions see more observing time, making TESS more sensitive to smaller and more distant planets in those systems. (NASA/MIT/TESS)

    Every system where an exoplanet is found by TESS will be remarkable, regardless of what type of star it is or what types of planets are found around it. You see, the goal of TESS is not, contrary to what many people think, to find an Earth-like world at the right distance from its parent star to have liquid water (and maybe life) on its surface. Sure, that would be awfully nice, but that’s not the purpose of TESS.

    Instead, the science goal of TESS is to find candidate exoplanets and candidate exoplanetary systems where future observatories ⁠ — like the James Webb Space Telescope ⁠ — can try to take detailed measurements of the planets themselves. This would include the capacity for measuring the atmospheric contents during transit, searching for potential biosignatures, or even, if we get lucky, the possibility of direct exoplanet imaging.

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    Hundreds of candidate planets have been discovered so far in the data collected and released by NASA’s Transiting Exoplanet Survey Satellite (TESS). Some of the closest worlds to be discovered by TESS will be candidates for being Earth-like and within the reach of direct imaging. (NASA/MIT/TESS)

    TESS was launched in April of 2018, and began taking its first scientific data in July of last year. It’s now been more than 12 months, which means that half of the sky (13 separate sets of observations of 27 days each) has now been observed by TESS. This coverage of the entire southern sky is unprecedented in terms of searches for nearby exoplanets, and while TESS now is turning to the northern hemisphere, let’s take a look at TESS’s discoveries so far:

    21 new exoplanets have been discovered, already confirmed by ground-based telescopes,

    ranging in size from as small as 0.80 times the size of Earth to larger than Jupiter,

    with an additional 850 candidate exoplanets that have been identified, awaiting ground-based confirmation,
    one system, Beta Pictoris, where exocomets (!) have been observed,

    and a small, super-Earth class planet orbiting very close to a Sun-like star that also possesses an enormous super- Jupiter on an extremely elliptical trajectory.

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    The Pi Mensae system was discovered to house an exoplanet way back in 2001: Pi Mensae b, with more than 10 Jupiter masses, and a huge difference between its closest approach (1.21 AU) and farthest distance (5.54 AU) from its parent star. TESS uncovered Pi Mensae c: a super-Earth with an orbital period of just 6.3 days. This marks the first time a nearby and distant planet with such different properties and orbits have been discovered around the same star. (NASA / MIT / TESS)

    But my favorite exoplanetary system investigated by TESS (so far) has to be the one around the nearby star HD 21749. It’s located 53 light-years away, it’s slightly smaller and less massive than our Sun (about 70% the mass and radius), and it now has two known planets around it.

    The first one discovered was HD 21749b, with 2.8 times the radius of Earth and 23.2 times the Earth’s mass. With a 36-day orbit, it should be on the warm side (about 300 °F/150 °C), slightly smaller but significantly denser than Uranus or Neptune. It is the longest-period exoplanet known within 100 light-years of Earth, and one of the best candidates in the TESS field for direct imaging.

    But the second planet, announced in April, is even better: HD 21749c was the first Earth-sized planet discovered by TESS, with Mercury-like temperatures, 90% the radius of Earth, and an orbital period of just 7.8 days.

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    An artist’s conception of HD 21749c, the first Earth-sized planet found by NASA’s Transiting Exoplanets Survey Satellite (TESS), as well as its sibling, HD 21749b, a warm sub-Neptune-sized world. (ROBIN DIENEL / CARNEGIE INSTITUTION FOR SCIENCE)

    There are huge advantages to what TESS is doing over what either Kepler or K2 did. Because TESS is preferentially measuring the nearest stars to us, identifying planets and planetary systems where follow-up observations will matter the most. The reason why is simple.

    1.When a planet orbits its star, it will be physically separated from it by some knowable, measurable distance.
    2.Depending on how far away the star is from us, that will correspond to an angular scale, with the planet achieving the largest angular separations from its star when it’s ¼ and ¾ of the way through its orbit relative to the moment of transit.
    3.Therefore, if you can identify the closest exoplanets with well-measured orbital parameters, you can use a high-resolution telescope equipped with a coronagraph to directly image the planet in question.

    As you may have guessed, the James Webb Space Telescope will have exactly the instrumentation and capabilities necessary to directly image many of these worlds.

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    The Near Infrared Camera (NIRCam) is Webb’s primary imager that will cover the infrared wavelength range 0.6 to 5 microns. NIRCam is equipped with coronagraphs, instruments that allow astronomers to take pictures of very faint objects around a central bright object, like stellar systems. NIRCam’s coronagraphs work by blocking a brighter object’s light, making it possible to view the dimmer object nearby. (LOCKHEED MARTIN)

    When it’s a bright, sunny day and you want to see an object in the sky that’s very close to the Sun, what do you do? You hold up a finger (or your whole hand) and block out the Sun, and then look for the nearby object that’s much intrinsically fainter than the Sun. This is exactly what telescopes equipped with coronagraphs do.

    With the next generation of telescopes, this will enable us to finally directly-image planets around the closest stars to us, but only if we know where, when, and how to look. This is exactly the type of information that astronomers are gaining from TESS. By the time the James Webb Space Telescope launches in 2021, TESS will have completed its first sweep of the entire sky, providing a rich suite of tantalizing targets suitable for direct imaging. Our first picture of an Earth-like world may well be close on the horizon. Thanks to TESS, we’ll know exactly where to look.

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    There are four known exoplanets orbiting the star HR 8799, all of which are more massive than the planet Jupiter. These planets were all detected by direct imaging taken over a period of seven years, with the periods of these worlds ranging from decades to centuries.

    Direct imaging-This false-color composite image traces the motion of the planet Fomalhaut b, a world captured by direct imaging. Credit: NASA, ESA, and P. Kalas (University of California, Berkeley and SETI Institute

    As in our Solar System, the inner planets revolve around their star more rapidly, and the outer planets revolve more slowly, as predicted by the law of gravity. With the next generation of telescopes like JWST, we may be able to measure Earth-like or super-Earth-like planets around the nearest stars to us. (JASON WANG / CHRISTIAN MAROIS)

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
  • richardmitnick 9:04 am on August 18, 2019 Permalink | Reply
    Tags: , , , , , Exoplanets, ,   

    From U Maryland via EarthSky: “Meet WASP-121b, a hot ‘heavy metal’ exoplanet” 

    U Maryland bloc

    From University of Maryland

    via

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    EarthSky

    For U Maryland
    July 31, 2019
    Matthew Wright,
    301-405-9267
    mewright@umd.edu

    For EarthSky
    August 18, 2019
    Paul Scott Anderson

    For the first time, heavy metal gases like magnesium and iron have been detected floating away from an exoplanet, a planet orbiting a distant sun. Why? Because the planet – which is about as big as Jupiter – is orbiting perilously close to its star.

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    Artist’s concept of WASP-121b, which orbits so close to its star and is so hot that heavy metal gases in its atmosphere are escaping into space. Image via Engine House VFX/At-Bristol Science Centre/University of Exeter/JPL.

    Exoplanets – worlds orbiting other stars – have been discovered in a wide variety of types and sizes, from small rocky worlds to sizzling hot gas giants orbiting close to their stars. The phrase “music of the spheres” comes to mind, an ancient philosophical concept that regarded the movements of the sun, moon and planets as a form of music. While that phrase tends to evoke thoughts of classical melodies, one exoplanet in particular seems to fit the heavy metal genre better.

    The planet – WASP-121b, a hot Jupiter 900 light-years from Earth – orbits so close to its star that its upper atmosphere is a sizzling 4,600 degrees Fahrenheit (2,500 Celsius). The gravity of its host star has distorted the planet into the oblong shape of an American football. First discovered in 2015, the planet is 1.8 times the mass of Jupiter.

    The Hubble Space Telescope (HST) detected gas escaping from the planet, iron and magnesium gas, dubbed “heavy metals.” These new peer-reviewed results were published on August 1 in The Astronomical Journal.

    Evidence suggests that the lower atmosphere of WASP-121b is so hot that iron and magnesium remain in a gaseous state. They stream to the upper atmosphere, where they can escape into space on the coattails of hydrogen and helium gas. This is the first time that such gases have been observed escaping a hot Jupiter exoplanet. As David Sing, a researcher at Johns Hopkins University in Baltimore, Maryland, said:

    “Heavy metals have been seen in other hot Jupiters before, but only in the lower atmosphere. So you don’t know if they are escaping or not. With WASP-121b, we see magnesium and iron gas so far away from the planet that they’re not gravitationally bound. The heavy metals are escaping partly because the planet is so big and puffy that its gravity is relatively weak. This is a planet being actively stripped of its atmosphere.”

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    Computer-simulated views of WASP-121b, using images from NASA’s Spitzer Space Telescope. Image via NASA/JPL-Caltech/Aix-Marseille University (AMU)/Wikipedia.

    How does this process occur? First, the star itself is hotter than the sun, and ultraviolet light from the star heats the planet’s upper atmosphere. The escaping iron and magnesium gas may also help to heat the atmosphere even more, according to Sing:

    “These metals will make the atmosphere more opaque in the ultraviolet, which could be contributing to the heating of the upper atmosphere.”

    Not only is the planet’s atmosphere severely affected, but so is the planet as well. It is actually approaching the point where it could be ripped apart by the star’s gravity. Right now though, it has been stretched into a football-like shape. WASP-121b offers a rare observation opportunity for scientists, as Sing noted:

    “We picked this planet because it is so extreme. We thought we had a chance of seeing heavier elements escaping. It’s so hot and so favorable to observe, it’s the best shot at finding the presence of heavy metals. We were mainly looking for magnesium, but there have been hints of iron in the atmospheres of other exoplanets. It was a surprise, though, to see it so clearly in the data and at such great altitudes so far away from the planet.”

    According to Drake Deming, an astronomer at the University of Maryland:

    “This planet is a prototype for ultra-hot Jupiters. These planets are so heavily irradiated by their host stars, they’re almost like stars themselves. The planet is being evaporated by its host star to the point that we can see metal atoms escaping the upper atmosphere where they can interact with the planet’s magnetic field. This presents an opportunity to observe and understand some very interesting physics.

    Hot Jupiters this close to their host star are very rare. Ones that are this hot are even rarer still. Although they’re rare, they really stand out once you’ve found them. We look forward to learning even more about this strange planet.”

    These observations of WASP-121b are part of the Panchromatic Comparative Exoplanetary Treasury Program (PanCET) survey. It is the first large-scale ultraviolet, visible, and infrared comparative study of 20 different exoplanets, ranging in size from super-Earths (several times Earth’s mass) to Jupiters (over 100 times Earth’s mass).

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    WASP-121b is a type of exoplanet called a hot Jupiter, like HD 209458b (artist’s concept). Image via NASA/ESA/G. Bacon (STScI)/N. Madhusudhan (UC).

    By studying WASP-121b and other hot Jupiters, scientists can learn more about how planets lose their primordial atmospheres. The atmospheres of still-forming planets tend to consist of the lighter-weight gases hydrogen and helium. But those atmospheres can be stripped away as a planet moves closer to its star. As Sing explained:

    “The hot Jupiters are mostly made of hydrogen, and Hubble is very sensitive to hydrogen, so we know these planets can lose the gas relatively easily. But in the case of WASP-121b, the hydrogen and helium gas is outflowing, almost like a river, and is dragging these metals with them. It’s a very efficient mechanism for mass loss.”

    WASP-121b is also an ideal target for future observations from the upcoming James Webb Space Telescope, which will be able to examine the atmosphere for water and carbon dioxide, and help provide a more complete analysis of all the chemical elements in the atmosphere. That data will help scientists better understand how worlds like hot Jupiters form, as well as planetary systems in general.

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    Artist’s concept of WASP-121b, which astronomers are describing as a heavy metal exoplanet. The planet is so hot that gases of magnesium and iron – called “heavy metals” because these elements’ atomic weights are greater than those of hydrogen or helium – are escaping its atmosphere. Meanwhile, the host star’s gravity is pulling on the planet and its atmosphere, stretching it into a football shape. Image via NASA/ESA/J. Olmsted (STScI)/Hubblesite.

    Bottom line: WASP-121b is a kind of hot Jupiter exoplanet rarely seen, a world so hot and so close to its star that heavy metal gases are being stripped from its atmosphere and the planet itself is being stretched into the shape of a football.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

    U Maryland Campus

    Driven by the pursuit of excellence, the University of Maryland has enjoyed a remarkable rise in accomplishment and reputation over the past two decades. By any measure, Maryland is now one of the nation’s preeminent public research universities and on a path to become one of the world’s best. To fulfill this promise, we must capitalize on our momentum, fully exploit our competitive advantages, and pursue ambitious goals with great discipline and entrepreneurial spirit. This promise is within reach. This strategic plan is our working agenda.

    The plan is comprehensive, bold, and action oriented. It sets forth a vision of the University as an institution unmatched in its capacity to attract talent, address the most important issues of our time, and produce the leaders of tomorrow. The plan will guide the investment of our human and material resources as we strengthen our undergraduate and graduate programs and expand research, outreach and partnerships, become a truly international center, and enhance our surrounding community.

    Our success will benefit Maryland in the near and long term, strengthen the State’s competitive capacity in a challenging and changing environment and enrich the economic, social and cultural life of the region. We will be a catalyst for progress, the State’s most valuable asset, and an indispensable contributor to the nation’s well-being. Achieving the goals of Transforming Maryland requires broad-based and sustained support from our extended community. We ask our stakeholders to join with us to make the University an institution of world-class quality with world-wide reach and unparalleled impact as it serves the people and the state of Maryland.

     
  • richardmitnick 2:04 pm on August 1, 2019 Permalink | Reply
    Tags: Exoplanets, ,   

    From Many Worlds: “Exoplanets Discoveries Flood in From TESS” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    August 1, 2019
    Marc Kaufman

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    NASA’s Transiting Exoplanet Survey Satellite (TESS) has hundreds of “objects of interest” waiting to be confirmed as planets in the data from the space telescope’s four cameras. These three were the first confirmed TESS discoveries, identified last year during its first three months of observing. By the time the mission is done, TESS’s wide-field cameras will have covered the whole sky in search of transiting exoplanets around 200,000 of the nearest (and brightest) stars. (NASA / MIT / TESS)

    NASA/MIT TESS replaced Kepler in search for exoplanets

    The newest space telescope in the sky–NASA’s Transiting Exoplanet Survey Satellite, TESS — has been searching for exoplanets for less than a year, but already it has quite a collection to its name.

    The TESS mission is to find relatively nearby planets orbiting bright and stable suns, and so expectations were high from the onset about the discovery of important new planets and solar systems. At a meeting this week at the Massachusetts Institute of Technology devoted to TESS results, principal investigator George Ricker pronounced the early verdict.

    The space telescope, he said, “has far exceeded our most optimistic hopes.” The count is up to 21 new planets and 850 additional candidate worlds waiting to be confirmed.

    Equally or perhaps more important is that the planets and solar systems being discovered promise important results. They have not yet included any Earth-sized rocky planet in a sun’s habitable zone — what is generally considered the most likely, though hardly the only, kind of planet to harbor life — but they did include planets that offer a great deal when it comes to atmospheres and how they can be investigated.

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    This infographic illustrates key features of the TOI 270 system, located about 73 light-years away in the southern constellation Pictor. The three known planets were discovered by NASA’s Transiting Exoplanet Survey Satellite through periodic dips in starlight caused by each orbiting world. Insets show information about the planets, including their relative sizes, and how they compare to Earth. Temperatures given for TOI 270’s planets are equilibrium temperatures, (NASA’s Goddard Space Flight Center/Scott Wiessinger)

    One of the newest three-planet system is called TOI-270, and it’s about 75 light years from Earth. The star at the center of the system is a red dwarf, a bit less than half the size of the sun.

    Despite its small size, it’s brighter than most of the nearby stars we know host planets. And it’s stable, making its solar system especially valuable. When variations in the star’s light are minimal, and they’re less likely to get in the way of trying to pick up subtle changes caused by its orbiting planets.

    While none of the three planets are likely habitable, more planets may yet be found farther out in the star system, orbiting in more habitable orbits. A paper describing the system was published in the journal Nature Astronomy.

    “This system is exactly what TESS was designed to find — small, temperate planets that pass, or transit, in front of an inactive host star, one lacking excessive stellar activity, such as flares,” said lead researcher Maximilian Günther, a Torres Postdoctoral Fellow at the (MIT) Kavli Institute for Astrophysics and Space Research in Cambridge.

    “This star is quiet and very close to us, and therefore much brighter than the host stars of comparable systems. With extended follow-up observations, we’ll soon be able to determine the make-up of these worlds, establish if atmospheres are present and what gases they contain, and more.”

    This is essential both in terms of understand the particular planet, and in developing methods for reading the atmospheres of exoplanets more generally. Those readings will hopefully some day tell researchers that they have found a planet with an atmosphere out of chemical balance in ways that could only be the result of biology.

    The authors estimate that the James Webb Space Telescope, now scheduled to launch in 2021, will eventually have a view of the system for over half the year, and it should be able to pick out the atmospheric signals for both planets.

    NASA/ESA/CSA Webb Telescope annotated

    As explained in a NASA release, the innermost planet, TOI 270 b, is likely a rocky world about 25% larger than Earth. It orbits the star every 3.4 days at a distance about 13 times closer than Mercury orbits the sun. Based on statistical studies of known exoplanets of similar size, the science team estimates TOI 270 b has a mass around 1.9 times greater than Earth’s.

    Due to its proximity to the star, planet b is an scalding-hot world. Its equilibrium temperature — that is, the temperature based only on energy it receives from the star, which ignores additional warming effects from a possible atmosphere — is around 490 degrees Fahrenheit (254 degrees Celsius).

    The other two planets, TOI 270 c and d, are, respectively, 2.4 and 2.1 times larger than Earth and orbit the star every 5.7 and 11.4 days. Although only about half its size, both may be similar to Neptune in our solar system, with compositions dominated by gases rather than rock. They likely weigh around 7 and 5 times Earth’s mass, respectively.

    All of the planets are expected to be tidally locked to the star, which means they only rotate once every orbit and keep the same side facing the star at all times, just as the Moon does in its orbit around Earth.

    Planet c and d might best be described as mini-Neptunes, a type of planet not seen in our own solar system. The researchers hope further exploration of TOI 270 may help explain how two of these mini-Neptunes formed alongside a nearly Earth-size world.

    “An interesting aspect of this system is that its planets straddle a well-established gap in known planetary sizes,” said co-author Fran Pozuelos, a postdoctoral researcher at the University of Liège in Belgium.

    “It is uncommon for planets to have sizes between 1.5 and two times that of Earth for reasons likely related to the way planets form, but this is still a highly controversial topic. TOI 270 is an excellent laboratory for studying the margins of this gap and will help us better understand how planetary systems form and evolve.”

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    Only 31 light-years away from Earth, the exoplanet GJ 357 d catches light from its host star GJ 357, in this artistic rendering.

    And then there’s the planetary system of GJ 357.

    The newly discovered planets orbit an M-type dwarf about one-third the sun’s mass and size and about 40% cooler that our star. The system is located 31 light-years away, which makes it a relatively close neighbor.

    In February, TESS cameras caught the star dimming slightly every 3.9 days, revealing the presence of a transiting exoplanet that passes across the face of its star during every orbit and briefly dims the star’s light. That discovery led to the finding of two more planets [Astronomy and Astrophysics] around the star, including one that may be quite promising.

    “In a way, these planets were hiding in measurements made at numerous observatories over many years,” said Rafael Luque, a doctoral student at the Institute of Astrophysics of the Canary Islands (IAC) on Tenerife, who led the discovery team.

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    IAC

    “It took TESS to point us to an interesting star where we could uncover them.”

    But while researchers were looking at ground-based data to confirm the existence of the hot Earth, they uncovered two additional worlds. The farthest-known planet, named GJ 357 d, is the one that really caught their attention.

    “GJ 357 d is located within the outer edge of its star’s habitable zone, where it receives about the same amount of stellar energy from its star as Mars does from the sun,” said co-author Diana Kossakowski at the Max Planck Institute for Astronomy in Heidelberg, Germany.


    Max Planck Institute for Astronomy campus, Heidelberg, Baden-Württemberg, Germany

    “If the planet has a dense atmosphere, which will take future studies to determine, it could trap enough heat to warm the planet and allow liquid water on its surface.”

    This GJ 357 system illustrates well how exoplanet discoveries are gathered, confirmed and then interpreted.

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    Transit data are rich with information. By measuring the depth of the dip in brightness and knowing the size of the star, scientists can determine the size or radius of the planet. The orbital period of the planet can be determined by measuring the elapsed time between transits. Once the orbital period is known, Kepler’s Third Law of Planetary Motion can be applied to determine the average distance of the planet from its stars. (NASA Ames)

    A planet orbiting GJ 357 was first identified via the transit method by TESS. Then it was confirmed using the ground-based radial velocity data collected from numerous ground-based telescopes over the years. That data was recoded and re-interpeted (with the assistance of the Carnegie Institution’s Paul Butler (who was part of the team that confirmed the detection of the first exoplanet in 1995) and the additional two planets were identified.

    9
    This artist’s illustration demonstrates the “wobble,” or radial velocity, technique for finding planets. The planet-detection technique relies on the fact that stars wobble back and forth as their planets circle around, tugging on them with their gravity. As a star moves toward us, the color of its light shifts to shorter, or bluer, wavelengths. As the star heads away, its light stretches into longer, or redder, wavelengths. The same principle, called the Doppler effect, causes sound from a speeding train to lower in pitch as it passes by.
    By measuring changes in the wavelength of light from a star, astronomers can track changes in the star’s velocity that arise from circling planets. By measuring the speed of the star and the period of the wobble, they can determine the mass and distance of the unseen planet, respectively. (NASA)

    Then the information was put through models by an interdisciplinary team and this announcement was the result:

    “An international team of astronomers… has characterized the first potentially habitable world outside of our own solar system.” The paper appeared in the journal Astrophysical Journal Letters.

    “This is exciting, as this is humanity’s first nearby super-Earth that could harbor life – uncovered with help from TESS, our small, mighty mission with a huge reach,” said Lisa Kaltenegger, associate professor of astronomy, director of Cornell’s Carl Sagan Institute and a member of the TESS science team.

    The exoplanet is more massive than our planet, and Kaltenegger said the discovery will provide insight into Earth’s heavyweight planetary cousins. “With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth, and we could pick out signs of life with telescopes that will soon be online,” she said.

    How did Kaltenegger and her colleagues get to that conclusion?

    The planet receives little more than a third of the radiation that Earth receives, making it similar to Mars. If the planet released gases present since its formation at a rate similar to Earth, the surface temperature would remain below freezing.

    But as their paper concludes:

    “Geological active worlds, like our Earth, are expected to build up CO2 concentrations due to the feedback of the carbonate-silicate cycle. We model atmospheres (with and without oxygen) as three examples, where we increase CO2 concentration so that the planet’s average surface temperature is above freezing.”

    “The sample reflection, emission and transmission spectra show features of a wide range of chemicals — water, carbon dioxide, methane, ozone and oxygen for Earth-like atmospheres from the Visible to Infrared wavelength — which would indicate habitability for observations with upcoming telescopes.”

    This is how the exoplanet drama works. Each significant discovery makes possible a future discovery, then additional hypotheses are put forward that often need new and more powerful viewing telescopes to prove or disprove. There are many goals in this enterprise, but the big one is clearly the discovery of clear signs of life far beyond Earth.

    See the full article here .


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    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 7:17 am on August 1, 2019 Permalink | Reply
    Tags: , , , , Exoplanets, , The new worlds orbit a star named GJ 357 an M-type dwarf about one-third the Sun’s mass and size and about 40% cooler that our star.   

    From NASA/MIT TESS: “Confirmation of Toasty TESS Planet Leads to Surprising Find of Promising World” 

    NASA/MIT TESS replaced Kepler in search for exoplanets

    NASA image
    From NASA/MIT TESS

    July 31, 2019
    Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    A piping hot planet discovered by NASA’s Transiting Exoplanet Survey Satellite (TESS) has pointed the way to additional worlds orbiting the same star, one of which is located in the star’s habitable zone. If made of rock, this planet may be around twice Earth’s size.

    The new worlds orbit a star named GJ 357, an M-type dwarf about one-third the Sun’s mass and size and about 40% cooler that our star. The system is located 31 light-years away in the constellation Hydra. In February, TESS cameras caught the star dimming slightly every 3.9 days, revealing the presence of a transiting exoplanet — a world beyond our solar system — that passes across the face of its star during every orbit and briefly dims the star’s light.


    Tour the GJ 357 system, located 31 light-years away in the constellation Hydra. Astronomers confirming a planet candidate identified by NASA’s Transiting Exoplanet Survey Satellite subsequently found two additional worlds orbiting the star. The outermost planet, GJ 357 d, is especially intriguing to scientists because it receives as much energy from its star as Mars does from the Sun. Credits: NASA’s Goddard Space Flight Center

    “In a way, these planets were hiding in measurements made at numerous observatories over many years,” said Rafael Luque, a doctoral student at the Institute of Astrophysics of the Canary Islands (IAC) on Tenerife who led the discovery team. “It took TESS to point us to an interesting star where we could uncover them.”

    The transits TESS observed belong to GJ 357 b, a planet about 22% larger than Earth. It orbits 11 times closer to its star than Mercury does our Sun. This gives it an equilibrium temperature — calculated without accounting for the additional warming effects of a possible atmosphere — of around 490 degrees Fahrenheit (254 degrees Celsius).

    “We describe GJ 357 b as a ‘hot Earth,’” explains co-author Enric Pallé, an astrophysicist at the IAC and Luque’s doctoral supervisor. “Although it cannot host life, it is noteworthy as the third-nearest transiting exoplanet known to date and one of the best rocky planets we have for measuring the composition of any atmosphere it may possess.”

    But while researchers were looking at ground-based data to confirm the existence of the hot Earth, they uncovered two additional worlds. The farthest-known planet, named GJ 357 d, is especially intriguing.

    2
    This diagram shows the layout of the GJ 357 system. Planet d orbits within the star’s so-called habitable zone, the orbital region where liquid water can exist on a rocky planet’s surface. If it has a dense atmosphere, which will take future studies to determine, GJ 357 d could be warm enough to permit the presence of liquid water. Credits: NASA’s Goddard Space Flight Center/Chris Smith

    “GJ 357 d is located within the outer edge of its star’s habitable zone, where it receives about the same amount of stellar energy from its star as Mars does from the Sun,” said co-author Diana Kossakowski at the Max Planck Institute for Astronomy in Heidelberg, Germany.


    Max Planck Institute for Astronomy, Heidelburg, GE

    “If the planet has a dense atmosphere, which will take future studies to determine, it could trap enough heat to warm the planet and allow liquid water on its surface.”

    Without an atmosphere, it has an equilibrium temperature of -64 F (-53 C), which would make the planet seem more glacial than habitable. The planet weighs at least 6.1 times Earth’s mass, and orbits the star every 55.7 days at a range about 20% of Earth’s distance from the Sun. The planet’s size and composition are unknown, but a rocky world with this mass would range from about one to two times Earth’s size.

    Even through TESS monitored the star for about a month, Luque’s team predicts any transit would have occurred outside the TESS observing window.

    GJ 357 c, the middle planet, has a mass at least 3.4 times Earth’s, orbits the star every 9.1 days at a distance a bit more than twice that of the transiting planet, and has an equilibrium temperature around 260 F (127 C). TESS did not observe transits from this planet, which suggests its orbit is slightly tilted — perhaps by less than 1 degree — relative to the hot Earth’s orbit, so it never passes across the star from our perspective.

    To confirm the presence of GJ 357 b and discover its neighbors, Luque and his colleagues turned to existing ground-based measurements of the star’s radial velocity, or the speed of its motion along our line of sight. An orbiting planet produces a gravitational tug on its star, which results in a small reflex motion that astronomers can detect through tiny color changes in the starlight. Astronomers have searched for planets around bright stars using radial velocity data for decades, and they often make these lengthy, precise observations publicly available for use by other astronomers.

    Luque’s team examined ground-based data stretching back to 1998 from the European Southern Observatory and the Las Campanas Observatory in Chile, the W.M. Keck Observatory in Hawaii, and the Calar Alto Observatory in Spain, among many others.

    ESO/Cerro LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    Carnegie Las Campanas Observatory in the southern Atacama Desert of Chile in the Atacama Region approximately 100 kilometres (62 mi) northeast of the city of La Serena,near the southern end and over 2,500 m (8,200 ft) high

    Calar Alto Observatory located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres

    A paper describing the findings was published on Wednesday, July 31, in the journal Astronomy & Astrophysics.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest dwarf stars in the sky. In a two-year survey of the solar neighborhood, TESS will monitor the brightness of stars for periodic drops caused by planet transits. The TESS mission is finding planets ranging from small, rocky worlds to giant planets, showcasing the diversity of planets in the galaxy.

    Astronomers predict that TESS will discover dozens of Earth-sized planets and up to 500 planets less than twice the size of Earth. In addition to Earth-sized planets, TESS is expected to find some 20,000 exoplanets in its two-year prime mission. TESS will find upwards of 17,000 planets larger than Neptune.

    TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Dr. George Ricker of MIT’s Kavli Institute for Astrophysics and Space Research serves as principal investigator for the mission. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT’s Lincoln Laboratory in Lexington, Massachusetts; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

    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 12:59 pm on May 23, 2019 Permalink | Reply
    Tags: "NASA Astrobiology Researchers Identify Features That Could Be Used to Detect Life-Friendly Climates on Other Worlds", , , , , , Exoplanets,   

    From NASA Goddard Space Flight Center: “NASA Astrobiology Researchers Identify Features That Could Be Used to Detect Life-Friendly Climates on Other Worlds” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Bill Steigerwald /
    NASA Goddard Space Flight Center, Greenbelt, Maryland
    301-286-8955 /
    william.a.steigerwald@nasa.gov /

    Nancy Jones
    NASA Goddard Space Flight Center, Greenbelt, Maryland
    301-286-0039
    nancy.n.jones@nasa.gov

    Scientists may have found a way to tell if alien worlds have a climate that is suitable for life by analyzing the light from these worlds for special signatures that are characteristic of a life-friendly environment. This technique could reveal the inner edge of a star’s habitable zone, the region around a star where liquid water could exist on the surface of a rocky planet.

    1
    Artist rendering of a red dwarf or M star, with three exoplanets orbiting. About 75 percent of all stars in the sky are the cooler, smaller red dwarfs. Credits: NASA/JPL-Caltech

    “Habitable planets by definition have water on their surfaces,” said Eric Wolf of the University of Colorado, Boulder. “However, water can come in the forms of ocean, ice, snow, vapor, or cloud. Each of these forms of water have very different effects on climate. However, each form also has specific effects that we may be able to detect on these planets, and use to determine whether or not a planet may have a habitable climate state.” Wolf is lead author of a paper on this research published May 22 in The Astrophysical Journal.

    Location determines value of real estate on Earth and in the cosmos as well. If a planet or planetary body is too close to its host star, the star’s intense light and heat cause the planet’s oceans to evaporate and eventually be lost to space. This climate state, called a “runaway greenhouse,” can be seen in our solar system on Venus, the next planet closer to the Sun than Earth. Venus is almost the same size as Earth and may have had oceans, but they vanished long ago as the planet’s proximity to the Sun caused a runaway greenhouse state. Now the parched surface of Venus swelters under an atmosphere about 100 times the pressure of Earth’s, with temperatures hot enough to melt lead. Conversely, if a planet or other planetary body is too far away from its host star, the oceans freeze, as can be seen in the icy moons of the outer solar system like Europa and Enceladus.

    2
    This image shows a view of the trailing hemisphere of Jupiter’s ice-covered satellite, Europa, in approximate natural color. Long, dark lines are fractures in the crust, some of which are more than 3,000 kilometers (1,850 miles) long. The bright feature containing a central dark spot in the lower third of the image is a young impact crater some 50 kilometers (31 miles) in diameter. This crater has been provisionally named “Pwyll” for the Celtic god of the underworld. Europa is about 3,160 kilometers (1,950 miles) in diameter, or about the size of Earth’s moon. This image was taken on September 7, 1996, at a range of 677,000 kilometers (417,900 miles) by the solid state imaging television camera onboard the Galileo spacecraft during its second orbit around Jupiter. The image was processed by Deutsche Forschungsanstalt fuer Luftund Raumfahrt e.V., Berlin, Germany. NASA/JPL/DLR

    3
    NASA’s Cassini spacecraft captured this view as it neared icy Enceladus for its closest-ever dive past the moon’s active south polar region. The view shows heavily cratered northern latitudes at top, transitioning to fractured, wrinkled terrain in the middle and southern latitudes. The wavy boundary of the moon’s active south polar region — Cassini’s destination for this flyby — is visible at bottom, where it disappears into wintry darkness. This view looks towards the Saturn-facing side of Enceladus. North on Enceladus is up and rotated 23 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Oct. 28, 2015. The view was acquired at a distance of approximately 60,000 miles (96,000 kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 45 degrees. Image scale is 1,896 feet (578 meters) per pixel.National Aeronautics and Space Administration (NASA) / Jet Propulsion Laboratory (JPL)

    Liquid water on a planet is a big deal because it’s necessary for life as we know it. Where there is liquid water, there may be life. The range where the distance is right for a climate that allows liquid water to persist on a planet’s surface is called the star’s “habitable zone”.

    Since we don’t have the ability to travel to planets around other stars (exoplanets) due to their enormous distances from us, we are limited to analyzing the light from exoplanets to search for a signal that the climate might be habitable. By separating this light into its component colors, or spectrum, scientists can identify the constituents of an exoplanet’s atmosphere, since different compounds emit and absorb distinct wavelengths (i.e. colors) of light. An exoplanet’s spectrum resembles a wavy line with peaks where the colors are bright and valleys where colors are dim. The researchers simulated an exoplanet’s emitted infrared spectrum, which is the heat-energy given out by an exoplanet, either due to its internal heat and/or the exoplanet heated by the star and then re-radiated. Infrared light is invisible to the human eye but detectable with special cameras and instruments on telescopes.

    In the new work, the researchers found that the appearance of the spectrum changes in distinct, signature ways for each climate state. “Different climate states — cold, warm and ‘runaway greenhouse’ which is very warm — have different amount of water-vapor in the atmosphere,” said Ravi Kopparapu, a co-author of the paper at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Different amounts of water vapor cause changes in the emitted radiation from the exoplanet, which changes the ‘spectra’, i.e., how much energy is emitted from each color and therefore how bright each color appears.”

    In the simulations, exoplanets much colder than Earth can still be habitable because they have small amounts of liquid water when these planets orbit close to the star. An ideal habitable exoplanet case is “temperate” with temperatures about the same as our Earth, and has elevated amounts of water vapor in the atmosphere compared to a cold exoplanet. The runaway greenhouse state has even more atmospheric water vapor. The findings raise the possibility that hot and moist climates, like a runaway greenhouse state, can potentially be identifiable in the appearance of the spectrum of exoplanets, and by observing how the spectrum changes as the exoplanet orbits its host star. According to Kopparapu, if correct, this gives a way to find the inner edge of the habitable zone with observations, which so far has only been simulated with climate models. The team is proposing a method to test this with observations.

    The idea of using an exoplanet’s emission and reflection spectrum to assess habitability has been proposed before. In the new work, the team simulated the spectra from exoplanets around a variety of stars smaller and fainter than our Sun, called M and K stars. They found specific features that could differentiate a runaway greenhouse state from habitable states, and hence, could be used to locate the inner edge of the habitable zone. The team used a 3-D climate model from the National Center for Atmospheric Research, called the Community Atmosphere Model, and modified it to suit for habitable exoplanets, naming it “ExoCAM”.

    See the full article here.


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.


    NASA/Goddard Campus

     
  • richardmitnick 11:17 am on March 29, 2019 Permalink | Reply
    Tags: Ana Humphrey, , , , , Exoplanets, , , ,   

    From NASA AMES: Women in STEM-“High School Senior Uncovers Potential for Hundreds of Earth-Like Planets in Kepler Data” Ana Humphrey 

    NASA Ames Icon

    From NASA AMES

    March 28, 2019
    Frank Tavares
    NASA’s Ames Research Center

    1
    Ana Humphrey

    An 18-year-old high school senior has won a $250,000 prize for calculating the potential for finding more planets outside our solar system, called exoplanets, using data from NASA’s Kepler space telescope.

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

    Kepler, whose mission ended in 2018, discovered over 2,600 confirmed exoplanets, with thousands more candidate planets still being considered. But are there more planets that have yet to be found around stars Kepler looked at, leaving traces in the telescope’s data? Ana Humphrey, a student at T.C. Williams High School in Alexandria, Virginia, has developed a mathematical model to find out. Her work calculated that there could be as many as 560 of these hidden planets and identified 96 areas of the sky where they might be found.

    For this research, Humphrey recently won first-place in the Regeneron Science Talent Search, the oldest science and math competition for high school seniors in the United States, produced by the Society for Science & the Public. As a Cuban-American student, she is the first Hispanic winner of the top award in the last 20 years.

    “I think it’s hard for a lot of students to see themselves doing something like astrophysics,” said Humphrey. “I hope my background will allow me to connect with students, especially Hispanic students, and get them to think about going into science.”

    2
    Ana Humphrey (left), Dr. Thomas Zurbuchen (middle) and Sophia Roberts (right) on the NASA Science Live talkshow where they discussed her work using Kepler data to find planets that orbit other stars.

    For Humphrey, winning this award is a dream she’s had since the sixth grade and the culmination of two years of research. Her inspiration for the project was the idea that new worlds could be discovered based on data from other objects, before being directly observed. Neptune, for example, was discovered in 1846 by looking at data from Uranus and its orbit, and there have been recent predictions of a hypothetical ninth planet beyond Pluto, based on the orbits of objects at the very edges of our solar system. Using this concept to search for exoplanets was a natural next step, she said.

    “I was completely fascinated by this idea of finding new planets using mass, based on data that we already had,” said Humphrey. “I think it just shows that even if your data collection is complete, there’s always new questions that can be asked and can be answered.”

    We know exoplanets are abundant – in fact, thanks to Kepler, we know there are more planets than stars in our galaxy. But in order to detect a planet, Kepler had to observe repeated dimmings of the brightness of a star as a planet passed by.

    Planet transit. NASA/Ames

    This is called the “transit method.” There are many planets left to be found that do not “transit” from the viewpoint of our telescopes, which means Kepler could not have found them. But Kepler data can lead to later discoveries of more planets that weren’t immediately obvious.

    Astrophysicist Elisa Quintana at NASA’s Goddard Space Flight Center, Greenbelt, Maryland is working with Humphrey as her mentor, exploring the idea that more planets could fit into systems that are already known. Quintana, who worked on the Kepler mission, also led the first discovery of an Earth-size planet in a habitable zone: Kepler-186f. The habitable zone is the area around a star where a planet could host liquid water. Kepler-186, a red dwarf star, is known to have five planets, but could potentially have more.

    “Take a system like Kepler-186,” Quintana said. “When we discovered the system, we noticed a big space between the four planets really close to the star and outer planet, enough where there could be another planet the size of Earth.”

    Many multi-planetary systems have similar gaps with the potential to house hidden Earth-size planets. Humphrey’s research aims to find out how many extra planets could fit into these systems, without disrupting the orbits we can observe.

    Her mathematical model places an “imagined” planet between two known exoplanets discovered by Kepler. Then, she uses two equations to describe how tight the space between the imagined planet and its two neighbors can be without disrupting their orbits. From this, she can use simple algebra to derive the possible mass and orbital distances of the hypothetical hidden planet. Using statistics, this model can determine not just if such a planet could exist, but the likelihood it’s actually there. When this technique is applied on the scale of a multi-planet star system, it reveals all the places planets might be hidden, and what those planets might look like.

    Humphrey designed her model so that it can be quickly applied to any exoplanet database. That means as more data comes in from the Transiting Exoplanet Survey Satellite (TESS), NASA’s active planet-hunting spacecraft, and other future missions, scientists can predict which planetary systems may have hidden planets there as well.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    She will continue working with Quintana to explore how likely it is that the hidden planets exist, and whether they can be detected with additional observations from other telescopes.

    Even before embarking on an astrophysics degree next year, Humphrey has already added an instrumental piece to the puzzle of searching for another life-harboring Earth in the cosmos. She plans to put her prize money toward her education and future research.

    “My goal going into any project is always to be the best scientist that I can be, to do the best research that I can do,” said Humphrey. “To get recognized by such a great award… I feel incredibly honored.”

    NASA’s Ames Research Center in California’s Silicon Valley 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 operated the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

    For more information about the Kepler and K2 missions, visit:

    http://www.nasa.gov/kepler

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Ames Research Center, one of 10 NASA field Centers, is located in the heart of California’s Silicon Valley. For over 60 years, Ames has led NASA in conducting world-class research and development. With 2500 employees and an annual budget of $900 million, Ames provides NASA with advancements in:
    Entry systems: Safely delivering spacecraft to Earth & other celestial bodies
    Supercomputing: Enabling NASA’s advanced modeling and simulation
    NextGen air transportation: Transforming the way we fly
    Airborne science: Examining our own world & beyond from the sky
    Low-cost missions: Enabling high value science to low Earth orbit & the moon
    Biology & astrobiology: Understanding life on Earth — and in space
    Exoplanets: Finding worlds beyond our own
    Autonomy & robotics: Complementing humans in space
    Lunar science: Rediscovering our moon
    Human factors: Advancing human-technology interaction for NASA missions
    Wind tunnels: Testing on the ground before you take to the sky

    NASA image

     
  • richardmitnick 8:58 pm on March 8, 2019 Permalink | Reply
    Tags: A new study explores whether magnetic fields cause this odd reversal, , , , , , Exoplanets, Exoplanets HAT-P-7b and CoRoT-2b have westward winds, Reversing Winds on Hot Jupiters, The majority of hot Jupiters have eastward equatorial winds   

    From AAS NOVA: “Reversing Winds on Hot Jupiters” 

    AASNOVA

    From AAS NOVA

    8 March 2019
    Susanna Kohler

    1
    Artist’s illustration of the hot Jupiter CoRoT-2b, with a hostspot that is offset westward. [NASA/JPL-Caltech/T. Pyle (IPAC)]

    Exoplanets HAT-P-7b and CoRoT-2b have an unusual quirk: instead of having eastward equatorial winds, like the majority of hot Jupiters, these two hot Jupiters have westward winds. A new study explores whether magnetic fields cause this odd reversal.

    Blowing the Wrong Way

    You might think that the hottest — and therefore brightest — part of a tidally locked hot Jupiter should be the part that directly faces its nearby host star. Surprisingly, our observations of hot Jupiters have generally revealed an offset for the peak brightness that’s slightly east of the point directly facing the host. These observations suggest that hot Jupiters host strong eastward-blowing winds near their equators that can displace their hottest point.

    Two planets break this rule, however: HAT-P-7b and CoRoT-2b. Observations of both of these hot Jupiters instead reveal hotspots that lie west of the point facing the host. Astronomers have generally interpreted this to imply that these two planets have westward-blowing equatorial winds — but why?

    There are a number of proposed explanations for this odd apparent reversal:

    1.The planet may not be tidally locked as expected; if it rotates on its axis slightly slower than it orbits its host, this could drive westward winds.
    2.The apparent offset hotspot location could be an illusion caused by asymmetric cloud distribution.
    3.Interactions of the planet’s magnetic field with its atmosphere could modify its wind pattern.

    In a new study led by Alexander Hindle (Newcastle University, UK), a team of scientists explores the feasibility of this third option.

    2
    Plot of the geopotential, which traces temperature, in the authors’ simulations, with (bottom) and without (top) the presence of magnetic fields. The hotspot (marked with a white cross) displaces to the east for the hydrodynamic case and to the west for the magnetohydrodynamic case. [Hindle et al. 2019]

    Magnetic Waves

    Hindle and collaborators use both analytic models and simulations to show what happens in the atmosphere of a planet with a strong magnetic field. They explore a layer of atmosphere that can behave like shallow water, developing planetary-scale waves. Without a magnetic field, these waves will naturally travel eastward. But in the presence of a strong toroidal magnetic field, the wave shears as it travels, resulting in westward-tilting eddies. This drives the winds to switch direction to the west.

    The authors next calculate the minimum magnetic field strength needed to create this equatorial wind reversal for planets with the properties of HAT-P-7b and CoRoT-2b. They find that an inflated hot Jupiter like HAT-P-7b would need a field strength above just 6 Gauss (for comparison, the Earth’s magnetic field is ~1 G). Estimated field strengths for inflated hot Jupiters lie in the 50–100 G range, so attributing HAT-P-7b’s wind reversal to magnetic fields is well within reason.

    For an ordinary hot Jupiter like CoRoT-2b, however, a field strength of 3,000 G is needed. The maximum expected field strength for a hot Jupiter like CoRoT-2b is 250 G, which isn’t sufficient to drive the reversal. Hindle and collaborators conclude that a different mechanism is likely at work on this planet.

    More observations of hot Jupiters in the future — as well as three-dimensional simulations — will help us to further understand the wind behavior in the atmospheres of these toasty planets.

    Citation

    “Shallow-water Magnetohydrodynamics for Westward Hotspots on Hot Jupiters,” A. W. Hindle et al 2019 ApJL 872 L27.
    https://iopscience.iop.org/article/10.3847/2041-8213/ab05dd/meta

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    1

    AAS Mission and Vision Statement

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

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

    Adopted June 7, 2009

     
  • richardmitnick 12:22 pm on January 5, 2019 Permalink | Reply
    Tags: , , , ‘Following the Water’, , , , Exoplanets, Fingerprinting Life, , , , , The habitable zone serves as a target selection tool, , , UCO Lick Observatory Mt Hamilton in San Jose California, UCR’s Alternative Earths Astrobiology Center   

    From UC Riverside: “Are We Alone?” 

    UC Riverside bloc

    From UC Riverside

    May 24, 2018
    Sarah Nightingale

    1
    Illustration by The Brave Union

    Forty years ago, the Voyager 2 spacecraft launched from Florida’s Cape Canaveral. Over the next decade, it swept across the solar system, sending back images of Jupiter’s volcanoes, Saturn’s rings, and for the first time, the icy atmospheres of Uranus and Neptune.

    NASA/Voyager 2

    2
    UCR’s Tim Lyons, left, and Stephen Kane are some of the only researchers in the world using Earth’s history as a guide to finding life in outer space. (Photo by Kurt Miller)

    The mission was more than enough to encourage Stephen Kane, a teenager growing up in Australia, to study planetary science in college. By the time he’d graduated, scientists had detected the first planet outside our solar system, known as an exoplanet, inspiring him to join the hunt and look for more.

    Over the past two decades, Kane, now an associate professor of planetary astrophysics at UC Riverside, has discovered hundreds of alien planets. At first, he focused on identifying giant Jupiter-like planets, which he describes as “low-hanging fruit” due to their large sizes. But in 2011, the Kepler Space Telescope identified the first rocky planet — Kepler 10b. Unlike gas giants such as Jupiter, rocky planets could potentially harbor life.

    NASA/Kepler Telescope

    With the discovery of more Earth-sized planets on the horizon, Kane realized that astrophysicists would struggle to understand the data they were receiving about terrestrial planets and their atmospheres.

    “During the course of the ongoing Kepler mission, I sought out planetary and Earth scientists because they’ve spent hundreds of years studying the solar system and how the Earth’s atmosphere has been shaped by biological and geophysical processes, so they have a lot to bring to the table,” Kane said.

    In 2017, Kane formalized that collaboration by joining an interdisciplinary research group led by Tim Lyons, a distinguished professor of biogeochemistry in the Department of Earth Sciences and director of UCR’s Alternative Earths Astrobiology Center. Backed by roughly $7.5 million from NASA, the center, one of only a handful like it in the world, brings together geochemists, biologists, planetary scientists, and astrophysicists from UCR and partner institutions to search for life on distant worlds using a template defined by the only known planet with life: Earth.

    3
    Astrobiology researchers study areas on Earth that hold evidence of ancient life, such as these stromatolites at the Hamelin Pool Marine Nature Reserve in Shark Bay, Australia. The rocky, dome-shaped structures formed in shallow water through the trapping of sedimentary grains by communities of microorganisms. (Photo by Mark Boyle)

    Fingerprinting Life

    Since its formation more than 4.5 billion years ago, Earth has undergone immense periods of geological and biological change.

    When the first life appeared — in the form of simple microbes — the sun was fainter, there were no continents, and there was no oxygen in the atmosphere. A new kind of life emerged around 2.7 billion years ago: photosynthetic bacteria that use the sun’s energy to convert carbon dioxide and water into food and oxygen gas. Multicellular life evolved from those bacteria, followed by more familiar lifeforms: fish about 530 million years ago, land plants 470 million years ago, and mammals 200 million years ago.

    “There are periods in the Earth’s past that are as different from one another as Earth is from an exoplanet,” Lyons said. “That is the concept of alternative Earths. You can slice the Earth’s history into chapters, pages, and even paragraphs, and there has been life evolving, thriving, surviving, and dying with each step. If we know what kind of atmospheres were present during the early stages of life on Earth, and their relationships to the evolving continents and oceans, we can look for similar signposts in our search for life on exoplanets.”

    While it might seem impossible to characterize ancient oceans and atmospheres, scientists can glean hints by studying rocks formed billions of years ago.

    “The chemical compositions of rocks are determined by the chemistry of the oceans and their life, and many of the gases in the atmosphere, through exchange with the oceans, are controlled by the same processes,” Lyons said. “These atmospheric fingerprints of life in the underlying oceans, or biosignatures, can be used as markers of life on other planets light years away.”

    The search for alien biosignatures typically centers on the gases produced by living creatures on Earth because they’re the only examples scientists have to work with. But Earth’s many chapters of inhabitation reveal the great number of possible gas combinations. Oxygen gas, ozone, and methane in a planet’s biosignature could all indicate the presence of life — and seeing them together could present an even stronger argument.

    The center’s search for life is different from the hunt for intelligent life. While those researchers probe for signs of alien civilizations, such as radio waves or powerful lasers, Lyons’ team is essentially looking for the byproducts of simple lifeforms.

    “As we’re exploring exoplanets, what we’re really trying to do is characterize their atmospheres,” he said. “If we see certain profiles of gases, then we may be detecting microbial waste products that are accumulating in the atmosphere.”

    The UCR team must also account for processes that produce the same gases without contributions from life, a phenomenon researchers call false positives. For example, a planetary atmosphere with abundant oxygen would be a promising biosignature, but that evidence could be misleading without fully addressing where it came from. Similarly, methane is a key biosignature, but there are many nonbiological ways to produce this gas on Earth. These distinctions require careful considerations of many factors, including seasonal patterns, tectonic activity, the type of planet and its star, among other data.

    False negatives are another concern, Lyons said. In previous research on ancient organic-rich rocks collected in Western Australia and South Africa, his group showed that about two billion years passed between the moment organisms first started producing oxygen on Earth and when it accumulated at levels high enough to be detectable in the atmosphere. In that scenario, a classic biosignature, oxygen, could be missed.

    “It’s also entirely possible that on some planets oxygen is produced through photosynthesis in pockets in the ocean and you’d never see it in the atmosphere,” Lyons said. “We have to be very clever to consider the many possibilities for biosignatures, and Earth’s past gives us many to choose from.”

    3
    Illustration by The Brave Union

    ‘Following the Water’

    With several hundred terrestrial planets confirmed and many more awaiting discovery, the search for life-bearing worlds is an almost overwhelming task.

    Astronomers are narrowing down their search by focusing on habitable zones — the orbital region around stars where it’s neither too hot nor too cold for liquid water to exist on the surface.

    “We know that liquid water is essential for life as we know it, and so we’re beginning our search by looking for planets that are capable of having similar environments to Earth. We call this approach ‘following the water,’” Kane said.

    While the habitable zone serves as a target selection tool, Kane said a planet nestled in this region won’t necessarily show signs of life — or even liquid water. Venus, for example, occupies the inner edge of the Sun’s habitable zone, but its scorching surface temperature has boiled away any liquid water that once existed.

    “We are extremely fortunate to have Venus in our solar system because it reminds us that a planet can be exactly the same size as Earth and still have things go catastrophically wrong,” Kane said.

    Equally important, being in the habitable zone doesn’t mean a planet will boast other factors that make Earth ideal for life. In addition to liquid water, the perfect candidate would have an insulating atmosphere and a protective magnetic field. It would also offer the right chemical ingredients for life and ways of recycling those elements over and over when continents collide, mountains lift up and wear down, and nutrients are swept back to the seas by rivers.

    “People question why we focus so intently on Earth, but the answer is obvious. We only know what we know about life because of what the Earth has given us,” said Lyons, who has spent decades reconstructing the conditions during which life evolved.

    “If I asked you to design a planet with the perfect conditions for life, you would design something just like Earth because it has all of these essential features,” he added. “We are studying how these building blocks have been assembled in different ways during Earth’s history and asking which of them are essential for life, which can be taken away. From that vantage point, we ask how they could be assembled in very different ways on other planets and still sustain life.”

    Kane said a distant planetary system called TRAPPIST-1, which NASA scientists discovered in 2017, could provide clues about the ingredients that are necessary for life.

    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).

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


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

    Although miniature compared to our own solar system — TRAPPIST-1 would easily fit inside Mercury’s orbit around the sun — it boasts seven planets, three of which are in the habitable zone. However, the planets don’t have moons, and they may not even have atmospheres.

    “We are finding that compact planetary systems orbiting faint stars are much more common than larger systems, so it’s important that we study them and find out if they could have habitable environments,” Kane said.

    4
    An artist’s illustration of the possible surface of TRAPPIST-1f, one of the planets in the TRAPPIST-1 system.

    Remote Observations

    At about 40 light-years (235 trillion miles) from Earth, the TRAPPIST-1 system is relatively close, but we’re never going to go there.

    “The fascinating thing about astronomy as a science is that it’s all based on remote observations,” Kane said. “We are trying to squeeze every piece of information we can out of photons that we are receiving from a very distant object.”

    While scientists have studied the atmospheres of several dozen exoplanets, most are too distant to probe with current instruments. That situation is changing. In April, NASA launched its Transiting Exoplanet Survey Satellite, known as TESS, which will seek Earth-sized planets around more than 500,000 nearby stars.

    NASA/MIT TESS

    In May 2020, NASA plans to launch the James Webb Space Telescope, which will perform atmospheric studies of the rocky worlds discovered by TESS.

    NASA/ESA/CSA Webb Telescope annotated

    Like Kepler, TESS detects exoplanets using the transit method, which measures the minute dimming of a star as an orbiting planet passes between it and the Earth.

    Planet transit. NASA/Ames

    Because light also passes through the atmosphere of planets, scientists will use the Webb telescope to identify the blanket of gases surrounding them through a technique called spectroscopy.

    Kane and Lyons are working with NASA to design missions that will directly image exoplanets in ways that will ensure that interdisciplinary teams such as theirs can properly interpret a wide variety of planetary processes.

    “As we design future missions, we must make sure they are equipped with the right instruments to detect biosignatures and geological processes, such as active volcanoes,” Kane said.

    UCR’s astrobiology team is one of only a few groups in the world studying ancient Earth to create a catalog of biosignatures that will inform mission design in NASA’s search for life on distant worlds. With quintillions — think the number of gallons of water in all of our oceans — of potentially habitable planets in the universe, Lyons said he is optimistic that we’ll find signs of life in the future.

    “Just like the Voyager missions were important because of what they taught us about our solar system — from the discovery of Jupiter’s rings to the first close-up glimpses of Uranus and Neptune — the TESS and James Webb missions, and more importantly the next generation of telescopes planned for the coming decades, are very likely to change our understanding of distant space,” Lyons said. And perhaps nestled in those discoveries will be an answer to the most fundamental of all questions, ‘are we alone?’

    Alternative Earths Astrobiology Center

    Founded in 2015

    One of 12 research teams funded by the NASA Astrobiology Institute, and one of only two using Earth’s history to guide exoplanet exploration

    Awarded $7.5 million over five years to cultivate a “search engine” for life on planets orbiting distant stars using Earth’s evolution over billions of years as a template

    Builds on existing UCR strengths in biogeochemistry, Earth history, and astrophysics

    Unites 66 researchers and staff at 11 institutions around the world, including primary partners led by former UCR graduate students now on the faculty at Yale and Georgia Tech

    4
    A NASA illustration of TESS monitoring stars outside our solar system.

    Through the Looking Glass

    In April, the Transiting Exoplanet Survey Satellite (TESS) Mission launched with the goal of discovering new Earths and super-Earths around nearby stars. As a guest investigator on the TESS Mission, Stephen Kane will use University of California telescopes, including those at the Lick Observatory in Mt. Hamilton to help determine whether candidate exoplanets identified by TESS are actually planets.

    UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)

    UCSC Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

    The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)

    UC Santa Cruz Shelley Wright at the 1-meter Nickel Telescope NIROSETI


    NIROSETI team from left to right Rem Stone UCO Lick Observatory Dan Werthimer UC Berkeley Jérôme Maire U Toronto, Shelley Wright UCSD Patrick Dorval U Toronto Richard Treffers Richard Treffers Starman Systems. (Image by Laurie Hatch)

    By studying the planet mass data obtained from the ground-based telescopes and planet diameter readings from spacecraft observations, Kane will also help determine the overall composition of the newly identified planets.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 12:57 pm on November 1, 2018 Permalink | Reply
    Tags: , , , , Exoplanets, , , ,   

    From Many Worlds: “The Kepler Space Telescope Mission Is Ending But Its Legacy Will Keep Growing” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-11-01
    Marc Kaufman

    NASA/Kepler Telescope

    As of October 2018, the planet-hunting spacecraft has been in space for nearly a decade. (NASA via AP)

    The Kepler Space Telescope is dead. Long live the Kepler.

    NASA officials announced on Tuesday that the pioneering exoplanet survey telescope — which had led to the identification of almost 2,700 exoplanets — had finally reached its end, having essentially run out of fuel. This is after nine years of observing, after a malfunctioning steering system required a complex fix and change of plants, and after the hydrazine fuel levels reached empty.

    While the sheer number of exoplanets discovered is impressive the telescope did substantially more: it proved once and for all that the galaxy is filled with planets orbiting distant stars. Before Kepler this was speculated, but now it is firmly established thanks to the Kepler run.

    It also provided data for thousands of papers exploring the logic and characteristics of exoplanets. And that’s why the Kepler will indeed live long in the world of space science.

    “As NASA’s first planet-hunting mission, Kepler has wildly exceeded all our expectations and paved the way for our exploration and search for life in the solar system and beyond,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington.

    “Not only did it show us how many planets could be out there, it sparked an entirely new and robust field of research that has taken the science community by storm. Its discoveries have shed a new light on our place in the universe, and illuminated the tantalizing mysteries and possibilities among the stars.”

    1
    The Kepler Space Telescope was focused on hunting for planets in this patch of the Milky Way. After two of its four spinning reaction wheels failed, it could no longer remain steady enough to stare that those distant stars but was reconfigured to look elsewhere and at a different angle for the K2 mission. (Carter Roberts/NASA)

    Kepler was initially the unlikely brainchild of William Borucki, its founding principal investigator who is now retired from NASA’s Ames Research Center in California’s Silicon Valley.

    3
    William Borucki, originally the main champion for the Kepler idea and later the principal investigator of the mission. His work at NASA went back to the Apollo days. (NASA)

    When he began thinking of designing and proposing a space telescope that could potentially tell us how common distant exoplanets were — and especially smaller terrestrial exoplanets like Earth – the science of extra solar planets was at a very different stage.

    “When we started conceiving this mission 35 years ago we didn’t know of a single planet outside our solar system,” Borucki said. “Now that we know planets are everywhere, Kepler has set us on a new course that’s full of promise for future generations to explore our galaxy.”

    The space telescope was launched in 2009. While Kepler did not find the first exoplanets — that required the work of astronomers using a different technique of observing based on the “wobble” of stars caused by orbiting planets — it did change the exoplanet paradigm substantially.

    Not only did it prove that exoplanets are common, it found that planets outnumber stars in our galaxy (which has hundreds of billions of those stars.)

    In addition it found that small, terrestrial-size planets are common as well, with some 20 to 50 percent of stars likely to have planets of that size and type. And what menagerie of planets it found out there.

    Among the greatest surprises: The Kepler mission provided data showing that the most common sized planets in the galaxy fall somewhere between Earth and Neptune, a type of planet that isn’t present in our solar system.

    It found solar systems of all sizes as well, including some with many planets (as many as eight) orbiting close to their host star.

    The discovery of these compact systems, generally orbiting a red dwarf star, raised questions about how solar systems form: Are these planets “born” close to their parent star, or do they form farther out and migrate in?

    So far, more than 2,500 peer-reviewed papers have been published using Kepler data, with substantial amounts of that data still unmined.

    Natalie Batalha was the project and mission scientist for Kepler for much of its run, and I asked her about its legacy.

    2
    Astrophysicist Natalie Batalha was the Kepler project and mission scientist for a decade. She left NASA recently for the University of California at Santa Cruz “to carry on the Kepler legacy” by creating an interdisciplinary center for the study of planetary habitability.

    “When I think of Kepler’s influence across all of astrophysics, I’m amazed at what such a simple experiment accomplished,” she wrote in an email. “You’d be hard-pressed to come up with a more boring mandate — to unblinkingly measure the brightnesses of the same stars for years on end. No beautiful images. No fancy spectra. No landscapes. Just dots in a scatter plot.

    “And yet time-domain astronomy exploded. We’d never looked at the Universe quite this way before. We saw lava worlds and water worlds and disintegrating planets and heart-beat stars and supernova shock waves and the spinning cores of stars and planets the age of the galaxy itself… all from those dots.”

    4
    The Kepler-62 system is but one of many solar systems detected by the space telescope. The planets within the green discs are in the habitable zones of the stars — where water could be liquid at times. (NASA)

    While Kepler provided remarkable answers to questions about the overall planetary makeup of our galaxy, it did not identify smaller planets that will be directly imaged, the evolving gold standard for characterizing exoplanets. The 150,000 stars that the telescope was observing were very distant, in the range of a few hundred to a few thousand light-years away. One light year is about 6 trillion (6,000,000,000,000) miles.

    Nonetheless, Kepler was able to detect the presence of a handful of Earth-sized planets in the habitable zones of their stars. The Kepler-62 system held one of them, and it is 1200 light-years away. In contrast, the four Earth-sized planets in the habitable zone of the much-studied Trappist-1 system are 39 light-years away.

    Kepler made its observations using the the transit technique, which looks for tiny dips in the amount of light coming from a star caused by the presence of a planet passing in front of the star. While the inference that exoplanets are ubiquitous came from Kepler results, the telescope was actually observing but a small bit of the sky. It has been estimated that it would require around 400 space telescopes like Kepler to cover the whole sky.

    What’s more, only planets whose orbits are seen edge-on from Earth can be detected via the transit method, and that rules out a vast number of exoplanets.

    The bulk of the stars that were selected for close Kepler observation were more or less sun-like, but a sampling of other stars occurred as well. One of the most important factors was brightness. Detecting minuscule changes in brightness caused by transiting planet is impossible if the star is too dim.

    Four years into the mission, after the primary mission objectives had been met, mechanical failures temporarily halted observations. The mission team was able to devise a fix, switching the spacecraft’s field of view roughly every three months. This enabled an extended mission for the spacecraft, dubbed K2, which lasted as long as the first mission and bumped Kepler’s count of surveyed stars up to more than 500,000.

    But it was inevitable that the mission would come to an end sooner rather than later because of that dwindling fuel supply, needed to keep the telescope properly pointed.

    Kepler cannot be refueled because NASA decided to place the telescope in an orbit around the sun that is well beyond the influence of the Earth and moon — to simplify operations and ensure an extremely quiet, stable environment for scientific observations. So Kepler was beyond the reach of any refueling vessel. The Kepler team compensated by flying considerably more fuel than was necessary to meet the mission objectives.

    The video below explains what will happen to the Kepler capsule once it is decommissioned. But a NASA release explains that the final commands “will be to turn off the spacecraft transmitters and disable the onboard fault protection that would turn them back on. While the spacecraft is a long way from Earth and requires enormous antennas to communicate with it, it is good practice to turn off transmitters when they are no longer being used, and not pollute the airwaves with potential interference.”

    And so Kepler will actually continue orbiting for many decades, just as its legacy will continue long after operations cease.

    Kepler’s follow-on exoplanet surveyor — the Transiting Exoplanet Survey Satellite or TESS — was launched this year and has begun sending back data.

    NASA/MIT TESS

    Its primary mission objective is to survey the brightest stars near the Earth for transiting exoplanets. The TESS satellite uses an array of wide-field cameras to survey some 85% of the sky, and is planned to last for two years.

    See the full article here .


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    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 2:53 pm on October 28, 2018 Permalink | Reply
    Tags: , , , , Exoplanets, ,   

    From JPL-Caltech: “Rocky? Habitable? Sizing up a Galaxy of Planets” 

    NASA JPL Banner

    From JPL-Caltech

    Oct. 25, 2018

    Calla Cofield
    Jet Propulsion Laboratory, Pasadena, Calif.
    626-808-2469
    calla.e.cofield@jpl.nasa.gov

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

    Written by Pat Brennan​

    1
    Artist’s concept of how rocky, potentially habitable worlds elsewhere in our galaxy might appear. Data gathered by telescopes in space and on the ground suggest that small, rocky planets are common. (Placing them so close together in a line is for illustrative purposes only.) Credits: NASA/JPL-Caltech/R. Hurt (SSC-Caltech)

    The planets so far discovered across the Milky Way are a motley, teeming multitude: hot Jupiters, gas giants, small, rocky worlds and mysterious planets larger than Earth and smaller than Neptune. As we prepare to add many thousands more to the thousands found already, the search goes on for evidence of life – and for a world something like our own.

    And as our space telescopes and other instruments grow ever more sensitive, we’re beginning to zero in.

    The discoveries so far inspire excitement and curiosity among scientists and the public. We’ve found rocky planets in Earth’s size range, at the right distance from their parent stars to harbor liquid water. While these characteristics don’t guarantee a habitable world – we can’t quite tell yet if these planets really do possess atmospheres or oceans – they can help point us in the right direction.

    Future space telescopes will be able to analyze the light from some of these planets, searching for water or a mixture of gases that resembles our own atmosphere. We will gain a better understanding of temperatures on the surface. As we continue checking off items on the habitability list, we’ll draw closer and closer to finding a world bearing recognizable signs of life.

    Among the most critical factors in the shaping and development of a habitable planet is the nature of its parent star. The star’s mass, size and age determine the distance and extent of its “habitable zone” – the region around a star where the temperature potentially allows for liquid water to pool on a planet’s surface.

    Star-mapping the Galaxy

    The European Space Agency’s Gaia satellite, launched in 2013, is becoming one of history’s greatest star mappers.

    ESA/GAIA satellite

    It relies on a suite of high-precision instruments to measure star brightness, distance, and composition. The ambitious goal is to create a three-dimensional map of our Milky Way galaxy. The chart so far includes the positions of about 1.7 billion stars, with distances for about 1.3 billion.

    That has prompted a reassessment of star sizes to learn whether some might be larger, smaller, dimmer or brighter than scientists had thought.

    It turns out that many of the stars were found to be brighter – and larger – than previous surveys estimated. For the team managing the explosion of planet finds from NASA’s Kepler space telescope, beginning in 2009, that also means a revision of sizes for the planets in orbit around them.

    NASA/Kepler Telescope

    If a star is brighter than we thought, it’s often larger than we thought as well. The planet in orbit around it, measured proportionally by the transit method, must also be larger.

    That means some of the planets thought to be of a size and temperature similar to Earth’s are really bigger – and usually, hotter.

    “Gaia has improved distances and has improved assessments of how bright a star is, and how big a planet is,” said Eric Mamajek, the deputy program chief scientist for NASA’s Exoplanet Exploration Program. “The whole issue has always been, how well do we understand the star? This is just another chapter of that ongoing story.”

    The latest scientific data from the Gaia space probe also is prompting a reassessment of the most promising “habitable zone” planets found by observatories around the world, as well as space-based instruments like NASA’s Kepler.

    Habitable planets Current Potential Planetary Habitability Laboratory U Puerto Rico Arecibo

    As scientists iron out both observations and definitions of what we consider a potentially habitable world, better data is bringing us closer to finding such a planet and – maybe just as important – finding our own planet’s place among them.

    Of the 3,700 exoplanets – planets around other stars – confirmed by scientists so far, about 2,600 were found by the Kepler space telescope. Kepler hunts for the tiny eclipse, or dip in starlight, as a planet crosses the face of its star.

    The most recent analysis of Kepler’s discoveries shows that 20 to 50 percent of the stars in the sky are likely to have small, potentially rocky planets in their habitable zones. Our initial estimate of near Earth-sized, habitable-zone planets from the Kepler spacecraft as of June 19, 2017, was 30. Preliminary analysis of newer data, on both those exoplanets and their host stars, shows that the number is likely smaller – possibly between 2 and 12.

    Much more data are needed, including a better understanding of how a planet’s size relates to its composition.

    “We’re still trying to figure out how big a planet can be and still be rocky,” said Jessie Dotson, an astrophysicist at NASA’s Ames Research Center in California’s Silicon Valley. She is also the project scientist for Kepler’s current, extended mission, known as K2.

    At first glance, the latest analysis might seem disappointing: fewer rocky, potentially habitable worlds among the thousands of exoplanets found so far. But that doesn’t change one of the most astonishing conclusions after more than 20 years of observation: Planets in the habitable zone are common.

    More and better data on these far distant planets means a more accurate demographic portrait of a universe of planets – and a more nuanced understanding of their composition, possible atmospheres and life-bearing potential.

    That should put us on more solid ground for the coming torrent of exoplanet discoveries from TESS (the Transiting Exoplanet Survey Satellite), and future telescopes as well. It brings us one step closer in our search for a promising planet among a galaxy of stars.

    “This is the exciting part of science,” Dotson said. “So often, we’re really portrayed as, ‘Now we know this story.’ But I have a theory: Scientists love it when we don’t know something. It’s the hunt that’s so exciting.”

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge, on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

    Caltech Logo

    NASA image

     
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