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  • richardmitnick 8:56 am on July 4, 2020 Permalink | Reply
    Tags: , , , , , NASA/MIT TESS, TESS mission discovers massive ice giant", The exoplanet UCF-1.01, TOI-849 b is the most massive Neptune-sized planet discovered to date and the first to have a density that is comparable to Earth.   

    From MIT News: “TESS mission discovers massive ice giant” 

    MIT News

    From MIT News

    July 1, 2020
    Jennifer Chu

    1
    In our solar system, the “ice giants” Neptune and Uranus are far less dense than rocky Venus and Earth. But astrophysicists on NASA’s TESS mission have now found an exoplanet, TOI-849b, that appears to be 40 times more massive than Earth, yet just as dense. This illustration depicts the exoplanet, UCF-1.01. Like TOI-849b, this exoplanet also orbits close to a star and is like “hot Neptune.” Image credit: NASA/JPL-Caltech.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    The “ice giant” planets Neptune and Uranus are much less dense than rocky, terrestrial planets such as Venus and Earth. Beyond our solar system, many other Neptune-sized planets, orbiting distant stars, appear to be similarly low in density.

    Now, a new planet discovered by NASA’s Transiting Exoplanet Survey Satellite, TESS, seems to buck this trend. The planet, named TOI-849 b, is the 749th “TESS Object of Interest” identified to date. Scientists spotted the planet circling a star about 750 light years away every 18 hours, and estimate it is about 3.5 times larger than Earth, making it a Neptune-sized planet. Surprisingly, this far-flung Neptune appears to be 40 times more massive than Earth and just as dense.

    TOI-849 b is the most massive Neptune-sized planet discovered to date, and the first to have a density that is comparable to Earth.

    “This new planet is more than twice as massive as our own Neptune, which is really unusual,” says Chelsea Huang, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research, and a member of the TESS science team. “Imagine if you had a planet with Earth’s average density, built up to 40 times the Earth’s mass. It’s quite crazy to think what’s happening at the center of a planet with that kind of pressure.”

    The discovery is reported today in the journal Nature. The study’s authors include Huang and members of the TESS science team at MIT.

    A blasted Jupiter?

    Since its launch on April 18, 2018, the TESS satellite has been scanning the skies for planets beyond our solar system. The project is one of NASA’s Astrophysics Explorer missions and is led and operated by MIT. TESS is designed to survey almost the entire sky by pivoting its view every month to focus on a different patch of the sky as it orbits the Earth. As it scans the sky, TESS monitors the light from the brightest, nearest stars, and scientists look for periodic dips in starlight that may signal that a planet is crossing in front of a star.

    Data taken by TESS, in the form of a star’s light curve, or measurements of brightness, is first made available to the TESS science team, an international, multi-institute group of researchers led by scientists at MIT. These researchers get a first look at the data to identify promising planet candidates, or TESS Objects of Interest. These are shared publicly with the general scientific community along with the TESS data for further analysis.

    For the most part, astronomers focus their search for planets on the nearest, brightest stars that TESS has observed. Huang and her team at MIT, however, recently had some extra time to look over data during September and October of 2018, and wondered if anything could be found among the fainter stars. Sure enough, they discovered a significant number of transit-like dips from a star 750 light years away, and soon after, confirmed the existence of TOI-849 b.

    “Stars like this usually don’t get looked at carefully by our team, so this discovery was a happy coincidence,” Huang says.

    Follow-up observations of the faint star with a number of ground-based telescopes further confirmed the planet and also helped to determine its mass and density.

    Huang says that TOI-849 b’s curious proportions are challenging existing theories of planetary formation.

    “We’re really puzzled about how this planet formed,” Huang says. “All the current theories don’t fully explain why it’s so massive at its current location. We don’t expect planets to grow to 40 Earth masses and then just stop there. Instead, it should just keep growing, and end up being a gas giant, like a hot Jupiter, at several hundreds of Earth masses.”

    One hypothesis scientists have come up with to explain the new planet’s mass and density is that perhaps it was once a much larger gas giant, similar to Jupiter and Saturn — planets with more massive envelopes of gas that enshroud cores thought to be as dense as the Earth.

    As the TESS team proposes in the new study, over time, much of the planet’s gassy envelope may have been blasted away by the star’s radiation — not an unlikely scenario, as TOI-849 b orbits extremely close to its host star. Its orbital period is just 0.765 days, or just over 18 hours, which exposes the planet to about 2,000 times the solar radiation that Earth receives from the sun. According to this model, the Neptune-sized planet that TESS discovered may be the remnant core of a much more massive, Jupiter-sized giant.

    “If this scenario is true, TOI-849 b is the only remnant planet core, and the largest gas giant core known to exist,” says Huang. “This is something that gets scientists really excited, because previous theories can’t explain this planet.”

    This research was funded, in part, by NASA.

    See the full article here .


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  • richardmitnick 1:46 pm on June 30, 2020 Permalink | Reply
    Tags: "NASA’s TESS Delivers New Insights Into an Ultrahot World", , , , , Kelt system- two robotic telescopes located in Arizona and South Africa., KELT transit survey, KELT-9 b- one of the hottest planets known., NASA/MIT TESS   

    From NASA/MIT TESS: “NASA’s TESS Delivers New Insights Into an Ultrahot World” 

    From NASA/MIT TESS

    June 30, 2020
    By Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Media contact:
    Claire Andreoli
    claire.andreoli@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.
    (301) 286-1940

    NASA/MIT TESS replaced Kepler in search for exoplanets

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    This illustration shows how planet KELT-9 b sees its host star. Over the course of a single orbit, the planet twice experiences cycles of heating and cooling caused by the star’s unusual pattern of surface temperatures. Between the star’s hot poles and cool equator, temperatures vary by about 1,500 F (800 C). This produces a “summer” when the planet faces a pole and a “winter” when it faces the cooler midsection. So every 36 hours, KELT-9 b experiences two summers and two winters. Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA)


    Explore KELT-9 b, one of the hottest planets known. Observations from NASA’s Transiting Exoplanet Survey Satellite (TESS) have revealed new details about the planet’s environment. The planet follows a close, polar orbit around a squashed star with different surface temperatures, factors that make peculiar seasons for KELT-9 b.

    Measurements from NASA’s Transiting Exoplanet Survey Satellite (TESS) have enabled astronomers to greatly improve their understanding of the bizarre environment of KELT-9 b, one of the hottest planets known.

    “The weirdness factor is high with KELT-9 b,” said John Ahlers, an astronomer at Universities Space Research Association in Columbia, Maryland, and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s a giant planet in a very close, nearly polar orbit around a rapidly rotating star, and these features complicate our ability to understand the star and its effects on the planet.”

    The new findings appear in a paper led by Ahlers published on June 5 in The Astronomical Journal.

    Located about 670 light-years away in the constellation Cygnus, KELT-9 b was discovered in 2017 because the planet passed in front of its star for a part of each orbit, an event called a transit. Transits regularly dim the star’s light by a small but detectable amount. The transits of KELT-9 b were first observed by the KELT transit survey, a project that collected observations from two robotic telescopes located in Arizona and South Africa.

    KELT Kilodegree Extremely Little Telescope at WINER Observatory in Arizona, USA c J.Peppe, operated by Ohio State, Vanderbilt and Lehigh universities

    2
    Winer Observatory in Sonoita, AZ, USA

    KELT South robotic telescope, Southerland, South Africa, jointly operated by Ohio State, Vanderbilt and Lehigh universities

    Between July 18 and Sept. 11, 2019, as part of the mission’s yearlong campaign to observe the northern sky, TESS observed 27 transits of KELT-9 b, taking measurements every two minutes. These observations allowed the team to model the system’s unusual star and its impact on the planet.

    KELT-9 b is a gas giant world about 1.8 times bigger than Jupiter, with 2.9 times its mass. Tidal forces have locked its rotation so the same side always faces its star. The planet swings around its star in just 36 hours on an orbit that carries it almost directly above both of the star’s poles.

    KELT-9 b receives 44,000 times more energy from its star than Earth does from the Sun. This makes the planet’s dayside temperature around 7,800 degrees Fahrenheit (4,300 C), hotter than the surfaces of some stars. This intense heating also causes the planet’s atmosphere to stream away into space.

    Its host star is an oddity, too. It’s about twice the size of the Sun and averages about 56 percent hotter. But it spins 38 times faster than the Sun, completing a full rotation in just 16 hours. Its rapid spin distorts the star’s shape, flattening it at the poles and widening its midsection. This causes the star’s poles to heat up and brighten while its equatorial region cools and dims — a phenomenon called gravity darkening. The result is a temperature difference across the star’s surface of almost 1,500 F (800 C).

    With each orbit, KELT-9 b twice experiences the full range of stellar temperatures, producing what amounts to a peculiar seasonal sequence. The planet experiences “summer” when it swings over each hot pole and “winter” when it passes over the star’s cooler midsection. So KELT-9 b experiences two summers and two winters every year, with each season about nine hours.

    “It’s really intriguing to think about how the star’s temperature gradient impacts the planet,” said Goddard’s Knicole Colón, a co-author of the paper. “The varying levels of energy received from its star likely produce an extremely dynamic atmosphere.”

    KELT-9 b’s polar orbit around its flattened star produces distinctly lopsided transits. The planet begins its transit near the star’s bright poles and then blocks less and less light as it travels over the star’s dimmer equator. This asymmetry provides clues to the temperature and brightness changes across the star’s surface, and they permitted the team to reconstruct the star’s out-of-round shape, how it’s oriented in space, its range of surface temperatures, and other factors impacting the planet.

    “Of the planetary systems that we’ve studied via gravity darkening, the effects on KELT-9 b are by far the most spectacular,” said Jason Barnes, a professor of physics at the University of Idaho and a co-author of the paper. “This work goes a long way toward unifying gravity darkening with other techniques that measure planetary alignment, which in the end we hope will tease out secrets about the formation and evolutionary history of planets around high-mass stars.”

    See the full article here .

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    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.

    NASA image

     
  • richardmitnick 1:35 pm on June 22, 2020 Permalink | Reply
    Tags: "Young Giant Planet Offers Clues to Formation of Exotic Worlds", HIP 67522 b, , NASA/MIT TESS   

    From NASA JPL-Caltech: “Young Giant Planet Offers Clues to Formation of Exotic Worlds” 

    NASA JPL Banner

    From NASA JPL-Caltech

    06.22.20

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

    NASA/Spitzer Infrared Telescope. No longer in service

    1
    HIP 67522 b

    Jupiter-size planets orbiting close to their stars have upended ideas about how giant planets form. Finding young members of this planet class could help answer key questions.

    For most of human history our understanding of how planets form and evolve was based on the eight (or nine) planets in our solar system. But over the last 25 years, the discovery of more than 4,000 exoplanets, or planets outside our solar system, changed all that.

    Among the most intriguing of these distant worlds is a class of exoplanets called hot Jupiters. Similar in size to Jupiter, these gas-dominated planets orbit extremely close to their parent stars, circling them in as few as 18 hours. We have nothing like this in our own solar system, where the closest planets to the Sun are rocky and orbiting much farther away. The questions about hot Jupiters are as big as the planets themselves: Do they form close to their stars or farther away before migrating inward? And if these giants do migrate, what would that reveal about the history of the planets in our own solar system?

    To answer those questions, scientists will need to observe many of these hot giants very early in their formation. Now, a new study in the Astronomical Journal reports on the detection of the exoplanet HIP 67522 b, which appears to be the youngest hot Jupiter ever found. It orbits a well-studied star that is about 17 million years old, meaning the hot Jupiter is likely only a few million years younger, whereas most known hot Jupiters are more than a billion years old. The planet takes about seven days to orbit its star, which has a mass similar to the Sun’s. Located only about 490 light-years from Earth, HIP 67522 b is about 10 times the diameter of Earth, or close to that of Jupiter. Its size strongly indicates that it is a gas-dominated planet.

    HIP 67522 b was identified as a planet candidate by NASA’s Transiting Exoplanet Survey Satellite (TESS), which detects planets via the transit method: Scientists look for small dips in the brightness of a star, indicating that an orbiting planet has passed between the observer and the star.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    Planet transit. NASA/Ames.

    But young stars tend to have a lot of dark splotches on their surfaces — starspots, also called sunspots when they appear on the Sun — that can look similar to transiting planets. So scientists used data from NASA’s recently retired infrared observatory, the Spitzer Space Telescope, to confirm that the transit signal was from a planet and not a starspot. (Other methods of exoplanet detection have yielded hints at the presence of even younger hot Jupiters, but none have been confirmed.)

    Radial Velocity Method-Las Cumbres Observatory

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

    Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964): 835

    The discovery offers hope for finding more young hot Jupiters and learning more about how planets form throughout the universe — even right here at home.

    “We can learn a lot about our solar system and its history by studying the planets and other things orbiting the Sun,” said Aaron Rizzutto, an exoplanet scientist at the University of Texas at Austin who led the study. “But we will never know how unique or how common our solar system is unless we’re out there looking for exoplanets. Exoplanet scientists are finding out how our solar system fits in the bigger picture of planet formation in the universe.”

    Migrating Giants?

    There are three main hypotheses for how hot Jupiters get so close to their parent stars. One is that they simply form there and stay put. But it’s hard to imagine planets forming in such an intense environment. Not only would the scorching heat vaporize most materials, but young stars frequently erupt with massive explosions and stellar winds, potentially dispersing any newly emerging planets.

    It seems more likely that gas giants develop farther from their parent star, past a boundary called the snow line, where it’s cool enough for ice and other solid materials to form. Jupiter-like planets are composed almost entirely of gas, but they contain solid cores. It would be easier for those cores to form past the snow line, where frozen materials could cling together like a growing snowball.

    The other two hypotheses assume this is the case, and that hot Jupiters then wander toward closer to their stars. But what would be the cause and timing of the migration?

    One idea posits that hot Jupiters begin their journey early in the planetary system’s history while the star is still surrounded by the disk of gas and dust from which both it and the planet formed. In this scenario, the gravity of the disk interacting with the mass of the planet could interrupt the gas giant’s orbit and cause it to migrate inward.

    The third hypothesis maintains that hot Jupiters get close to their star later, when the gravity of other planets around the star can drive the migration. The fact that HIP 67522 b is already so close to its star so early after its formation indicates that this third hypothesis probably doesn’t apply in this case. But one young hot Jupiter isn’t enough to settle the debate on how they all form.

    “Scientists would like to know if there is a dominant mechanism that forms most hot Jupiters,” said Yasuhiro Hasegawa, an astrophysicist specializing in planet formation at NASA’s Jet Propulsion Laboratory who was not involved in the study. “In the community right now there is no clear consensus about which formation hypothesis is most important for reproducing the population we have observed. The discovery of this young hot Jupiter is exciting, but it’s only a hint at the answer. To solve the mystery, we will need more.”

    TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center. 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; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

    NASA’s Spitzer Space Telescope was retired on Jan. 30, 2020. Science data continues to be analyzed by the science community via the Spitzer data archive located at the Infrared Science Archive housed at IPAC at Caltech in Pasadena, California. JPL managed Spitzer mission operations for NASA’s Science Mission Directorate in Washington. Science operations were conducted at the Spitzer Science Center at IPAC at Caltech. Spacecraft operations were based at Lockheed Martin Space in Littleton, Colorado. Caltech manages JPL for NASA.

    See the full article here .


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    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.

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    NASA image

     
  • richardmitnick 9:22 am on May 14, 2020 Permalink | Reply
    Tags: "Hawaii Astronomers Help Decipher Rhythm Among Young Stars", , , , , Delta scuti variable stars, , NASA/MIT TESS   

    From Keck Observatory: “Hawaii Astronomers Help Decipher Rhythm Among Young Stars” 

    Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

    From Keck Observatory

    1
    The delta scuti variable star called hd 31901. Credit: Chris Boshuizen, Simon Murphy, Tim Bedding

    By “listening” to the “beating hearts” of stars, an international team of astronomers, including researchers from the University of Hawai’i Institute for Astronomy (UH IfA), detected a rhythm of life for a class of stellar objects that puzzled scientists until now.

    The findings are an important contribution to the overall understanding of what goes on inside trillions of stars across the cosmos.

    UH IfA Assistant Professor Daniel Huber and School of Ocean and Earth Science and Technology (SOEST) Professor Eric Gaidos co-authored the study, which includes observations from W. M. Keck Observatory on Maunakea in Hawaii; the paper published today in the science journal Nature.

    “The signals from these stars have been a mystery for over a hundred years,” Huber said. “We knew that brightness variations in these stars are caused by sound waves traveling in their interior, but we just couldn’t make any sense of them.”

    The international team led by Professor Tim Bedding at the University of Sydney used data from NASA’s Transiting Exoplanet Survey Satellite (TESS), a space telescope used to detect planets around nearby stars.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    It provided the team with brightness measurements of thousands of stars, allowing them to find 60 whose pulsations were ripe for study.

    “NASA’s TESS data has delivered precise detections in a much larger number of these stars than we had before. This has now finally cleared up the picture, and we were able to identify regular structures. It’s like notes of a song finally falling into place to play a beautiful melody,” Huber explained.


    Simulation of pulsations in the Delta Scuti variable star called HD 31901, based on brightness measurements by NASA’s Transiting Exoplanet Survey Satellite (TESS). The simulation has been sped up by a factor of 2646 so that 24 hours of TESS data lasts 33 seconds. CREDIT: C. BOSHUIZEN/S. MURPHY/T. BEDDING

    A WINDOW TO OUR PAST

    The stars analyzed in the study are about 1.5 to 2.5 times more massive than the Sun and are known as Delta Scuti stars. Within the past few decades, astronomers have been able to detect the internal oscillations of stars, revealing their structure by studying stellar pulsations using careful and precise measurements of changes in light output. Over periods of time, brightness variations reveal intricate—and often regular—patterns, allowing researchers to stare into the very heart of the massive nuclear furnaces that light the universe. This branch of science, known as asteroseismology, enables astronomers to understand the insides of distant stars similar to how earthquakes are used to decipher the interior structure of our planet.

    The research team’s identification of regular patterns in Delta Scuti stars will dramatically expand the reach of asteroseismology.

    “Young stars like these are among the most intriguing and important objects in astronomy,” said Gaidos. “They allow us to see how stars and their planets form and change with time much as the Solar System did more than 4 billion years ago. They are a window into our past.”

    KECK OBSERVATORY CONTRIBUTES

    Observations using Keck Observatory’s High-Resolution Echelle Spectrometer (HIRES) provided critical information during the study to explain the brightness variations of the stars recorded by TESS.

    Keck Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope, Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft) above sea level

    “Our observations with Keck showed that most Delta Scuti stars with regular patterns appear to be spinning slower than normal,” Huber said. “We believe that this is one of the key pieces to explain their clear frequency patterns, and this will be critical to find more of them in the future.”

    “This is really exciting work,” said John O’Meara, chief scientist at Keck Observatory. “It uses the combination of HIRES and TESS, data usually focused on finding exoplanets, to look deep into the hearts of stars and start to solve another mystery about them. I look forward to more of these types of measurements as the TESS mission goes on; Keck and HIRES are ready.”

    NASA has funded multiple TESS-related research projects at UH totaling nearly one million dollars at the university since the launch of the TESS telescope in April 2018.

    See the full article here .


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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

     
  • richardmitnick 5:42 pm on January 8, 2020 Permalink | Reply
    Tags: "NASA’s new exoplanet hunter found its first potentially habitable world", , , , , , , NASA/MIT TESS, Planet TOI 700 d   

    From MIT Technology Review: “NASA’s new exoplanet hunter found its first potentially habitable world” 

    MIT Technology Review
    From MIT Technology Review

    1.8.20
    Neel V. Patel

    1
    TOI 700 d

    NASA’s Transiting Exoplanet Survey Satellite (TESS) has just found a new potentially habitable exoplanet the size of Earth, located about 100 light-years away. It’s the first potentially habitable exoplanet the telescope has found since it was launched in April 2018.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    It’s called TOI 700 d [science paper https://arxiv.org/abs/2001.00952 ]. It orbits a red dwarf star about 40% less massive than the sun and half as cool. The planet itself is about 1.2 times the size of Earth and orbits the host star every 37 days, receiving close to 86% of the amount of sunlight Earth does.

    Most notably, TOI 700 d is in what’s thought to be its star’s habitable zone, meaning it’s at a distance where temperatures ought to be moderate enough to support liquid water on the surface. This raises hopes TOI 700 d could be amenable to life—even though no one can agree on what it means for a planet to be habitable.

    A set of 20 different simulations meant to model TOI 700 d suggest the planet is rocky and has an atmosphere that helps it retain water, but there’s a chance it might simply be a gaseous mini-Neptune. We won’t know for sure until follow-up observations are made with some sharper instruments, such as the upcoming James Webb Space Telescope, which is planned for launch in March 2021.

    NASA/ESA/CSA Webb Telescope annotated

    TESS finds exoplanets using the tried-and-true technique of looking for objects as they’re transiting in front of their host stars.

    Planet transit. NASA/Ames

    Data from NASA’s Spitzer Space Telescope was also used to get some closer measurements of the planet’s size and orbit.

    NASA/Spitzer Infrared Telescope

    Tess is NASA’s newest exoplanet-hunting space telescope, the successor to the renowned Kepler Space Telescope that was used to find some 2,600 exoplanets.

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

    TESS, able to survey 85% of the night sky (400 times more than what Kepler could monitor), is about to finish its primary two-year mission but has fallen woefully short of expectations. NASA initially thought TESS was going to find more than 20,000 transiting exoplanets, but with only months left it has only identified 1,588 candidates. Even so, the telescope’s mission will almost surely be extended.

    See the full article here .


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    The mission of MIT Technology Review is to equip its audiences with the intelligence to understand a world shaped by technology.

     
  • richardmitnick 1:33 pm on January 7, 2020 Permalink | Reply
    Tags: "NASA’s TESS Mission Uncovers Its 1st World with Two Stars", , , , , NASA/MIT TESS,   

    From SETI Institute: “NASA’s TESS Mission Uncovers Its 1st World with Two Stars” 

    SETI Logo new
    From SETI Institute

    Jan 6, 2020
    Rebecca McDonald
    Director of Communications
    SETI Institute
    rmcdonald@seti.org
    650-960-4526

    Written by
    Jeanette Kazmierczak
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1
    TOI 1338 b is silhouetted by its host stars. TESS only detects transits from the larger star. Credit: NASA’s Goddard Space Flight Center/Chris Smith.

    In 2019, when Wolf Cukier finished his junior year at Scarsdale High School in New York, he joined NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as a summer intern. His job was to examine variations in star brightness captured by NASA’s Transiting Exoplanet Survey Satellite (TESS) and uploaded to the Planet Hunters TESS citizen science project.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    “I was looking through the data for everything the volunteers had flagged as an eclipsing binary, a system where two stars circle around each other and from our view eclipse each other every orbit,” Cukier said. “About three days into my internship, I saw a signal from a system called TOI 1338. At first I thought it was a stellar eclipse, but the timing was wrong. It turned out to be a planet.”

    TOI 1338 b, as it is now called, is TESS’s first circumbinary planet, a world orbiting two stars. The discovery was featured in a panel discussion on Monday, Jan. 6, at the 235th American Astronomical Society meeting in Honolulu. A paper, which Cukier co-authored along with scientists from Goddard, San Diego State University, the University of Chicago and other institutions, has been submitted to a scientific journal.

    The TOI 1338 system lies 1,300 light-years away in the constellation Pictor. The two stars orbit each other every 15 days. One is about 10% more massive than our Sun, while the other is cooler, dimmer and only one-third the Sun’s mass.

    TOI 1338 b is the only known planet in the system. It’s around 6.9 times larger than Earth, or between the sizes of Neptune and Saturn. The planet orbits in almost exactly the same plane as the stars, so it experiences regular stellar eclipses.

    TESS has four cameras, which each take a full-frame image of a patch of the sky every 30 minutes for 27 days. Scientists use the observations to generate graphs of how the brightness of stars change over time. When a planet crosses in front of its star from our perspective, an event called a transit, its passage causes a distinct dip in the star’s brightness.

    Planet transit. NASA/Ames

    But planets orbiting two stars are more difficult to detect than those orbiting one. TOI 1338 b’s transits are irregular, between every 93 and 95 days, and vary in depth and duration thanks to the orbital motion of its stars. TESS only sees the transits crossing the larger star; the transits of the smaller star are too faint to detect.

    “These are the types of signals that algorithms really struggle with,” said lead author Veselin Kostov, a research scientist at the SETI Institute and Goddard. “The human eye is extremely good at finding patterns in data, especially non-periodic patterns like those we see in transits from these systems.”

    This explains why Cukier had to visually examine each potential transit. For example, he initially thought TOI 1338 b’s transit was a result of the smaller star in the system passing in front of the larger one — both cause similar dips in brightness. But the timing was wrong for an eclipse.

    After identifying TOI 1338 b, the research team used a software package called eleanor, named after Eleanor Arroway, the central character in Carl Sagan’s novel “Contact,” to confirm the transits were real and not a result of instrumental artifacts.

    “Throughout all of its images, TESS is monitoring millions of stars,” said co-author Adina Feinstein, a graduate student at the University of Chicago. “That’s why our team created eleanor. It’s an accessible way to download, analyze and visualize transit data. We designed it with planets in mind, but other members of the community use it to study stars, asteroids and even galaxies.”

    TOI 1338 had already been studied from the ground by radial velocity surveys, which measure motion along our line of sight. Kostov’s team used this archival data to analyze the system and confirm the planet. Although the planet transits irregularly, its orbit is stable for at least the next 10 million years. The orbit’s angle to us, however, changes enough that the planet transit will cease after November 2023 and resume eight years later.

    NASA’s Kepler and K2 missions previously discovered 12 circumbinary planets in 10 systems, all similar to TOI 1338 b.

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

    Observations of binary systems are biased toward finding larger planets, Kostov said. Transits of smaller bodies don’t have as big an effect on the stars’ brightness. TESS is expected to observe hundreds of thousands of eclipsing binaries during its initial two-year mission, so many more of these circumbinary planets should be waiting for discovery.


    NASA’s Transiting Exoplanet Survey Satellite found its first circumbinary planet, a world orbiting two stars 1,300 light-years away. Watch to learn more about this Saturn-size world called TOI 1338 b.
    Credit: NASA’s Goddard Space Flight Center

    TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center. 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; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

    See the full article here.

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    SETI Institute


    About the SETI Institute
    What is life? How does it begin? Are we alone? These are some of the questions we ask in our quest to learn about and share the wonders of the universe. At the SETI Institute we have a passion for discovery and for passing knowledge along as scientific ambassadors.

    The SETI Institute is a 501 (c)(3) nonprofit scientific research institute headquartered in Mountain View, California. We are a key research contractor to NASA and the National Science Foundation (NSF), and we collaborate with industry partners throughout Silicon Valley and beyond.

    Founded in 1984, the SETI Institute employs more than 130 scientists, educators, and administrative staff. Work at the SETI Institute is anchored by three centers: the Carl Sagan Center for the Study of Life in the Universe (research), the Center for Education and the Center for Outreach.

    The SETI Institute welcomes philanthropic support from individuals, private foundations, corporations and other groups to support our education and outreach initiatives, as well as unfunded scientific research and fieldwork.

    A Special Thank You to SETI Institute Partners and Collaborators
    • Campoalto, Chile, NASA Ames Research Center, NASA Headquarters, National Science Foundation, Aerojet Rocketdyne,SRI International

    Frontier Development Lab Partners
    • Breakthrough Prize Foundation, European Space Agency, Google Cloud, IBM, Intel, KBRwyle. Kx Lockheed Martin, NASA Ames Research Center, Nvidia, SpaceResources Luxembourg, XPrize

    In-kind Service Providers
    • Gunderson Dettmer – General legal services, Hello Pilgrim – Website Design and Development Steptoe & Johnson – IP legal services, Danielle Futselaar

    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA, Altitude 986 m (3,235 ft)

    SETI Institute – 189 Bernardo Ave., Suite 100
    Mountain View, CA 94043
    Phone 650.961.6633 – Fax 650-961-7099
    Privacy PolicyQuestions and Comments

    Also in the hunt, but not a part of the SETI Institute


    SETI@home, a BOINC project originated in the Space Science Lab at UC Berkeley

    BOINCLarge

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

     
  • richardmitnick 12:02 pm on December 31, 2019 Permalink | Reply
    Tags: , , , , , ESA’s Characterising Exoplanet Satellite Cheops, , Future giant ground based optical telescopes, , NASA/MIT TESS   

    From ars technica: “The 2010s: Decade of the exoplanet” 

    Ars Technica
    From ars technica

    12/31/2019
    John Timmer

    1
    Artist conception of Kepler-186f, the first Earth-size exoplanet found in a star’s “habitable zone.”

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

    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

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    The last ten years will arguably be seen as the “decade of the exoplanet.” That might seem like an obvious thing to say, given that the discovery of the first exoplanet was honored with a Nobel Prize this year. But that discovery happened back in 1995—so what made the 2010s so pivotal?

    One key event: 2009’s launch of the Kepler planet-hunting probe.

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

    Kepler spawned a completely new scientific discipline, one that has moved from basic discovery—there are exoplanets!—to inferring exoplanetary composition, figuring out exoplanetary atmosphere, and pondering what exoplanets might tell us about prospects for life outside our Solar System.

    To get a sense of how this happened, we talked to someone who was in the field when the decade started: Andrew Szentgyorgyi, currently at the Harvard-Smithsonian Center for Astrophysics, where he’s the principal investigator on the Giant Magellan Telescope’s Large Earth Finder instrument.

    Giant Magellan Telescope, 21 meters, to be at the Carnegie Institution for Science’s Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high

    In addition to being famous for having taught your author his “intro to physics” course, Szentgyorgyi was working on a similar instrument when the first exoplanet was discovered.

    Two ways to find a planet

    The Nobel-winning discovery of 51 Pegasi b came via the “radial velocity” method, which relies on the fact that a planet exerts a gravitational influence on its host star, causing the star to accelerate slightly toward the planet.

    Radial Velocity Method-Las Cumbres Observatory

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

    Unless the planet’s orbit is oriented so that it’s perpendicular to the line of sight between Earth and the star, some of that acceleration will draw the star either closer to or farther from Earth. This acceleration can be detected via a blue or red shift in the star’s light, respectively.

    The surfaces of stars can expand and contract, which also produces red and blue shifts, but these won’t have the regularity of acceleration produced by an orbital body. But it explains why, back in the 1990s, people studying the surface changes in stars were already building the necessary hardware to study radial velocity.

    “We had a group that was building instruments that I’ve worked with to study the pulsations of stars—astroseismology,” Szentgyorgyi told Ars, “but that turns out to be sort of the same instrumentation you would use” to discern exoplanets.

    He called the discovery of 51 Pegasi b a “seismic event” and said that he and his collaborators began thinking about how to use their instruments “probably when I got the copy of Nature” that the discovery was published in. Because some researchers already had the right equipment, a steady if small flow of exoplanet announcements followed.

    During this time, researchers developed an alternate way to find exoplanets, termed the “transit method.”

    Planet transit. NASA/Ames

    The transit method requires a more limited geometry from an exoplanet’s orbit: the plane has to cause the exoplanet to pass through the line of sight between its host star and Earth. During these transits, the planet will eclipse a small fraction of light from the host star, causing a dip in its brightness. This doesn’t require the specialized equipment needed for radial velocity detections, but it does require a telescope that can detect small brightness differences despite the flicker caused by the light passing through our atmosphere.

    By 2009, transit detections were adding regularly to the growing list of exoplanets.

    The tsunami

    In the first year it was launched, Kepler started finding new planets. Given time and a better understanding of how to use the instrument, the early years of the 2010s saw thousands of new planets cataloged. In 2009, Szentgyorgyi said, “it was still ‘you’re finding handfuls of exoplanetary systems.’ And then with the launch of Kepler, there’s this tsunami of results which has transformed the field.”

    Suddenly, rather than dozens of exoplanets, we knew about thousands.

    2
    The tsunami of Kepler planet discoveries.

    The sheer numbers involved had a profound effect on our understanding of planet formation. Rather than simply having a single example to test our models against—our own Solar System—we suddenly had many systems to examine (containing over 4,000 currently known exoplanets). These include objects that don’t exist in our Solar System, things like hot Jupiters, super-Earths, warm Neptunes, and more. “You found all these crazy things that, you know, don’t make any sense from the context of what we knew about the Solar System,” Szentgyorgyi told Ars.

    It’s one thing to have models of planet formation that say some of these planets can form; it’s quite another to know that hundreds of them actually exist. And, in the case of hot Jupiters, it suggests that many exosolar systems are dynamic, shuffling planets to places where they can’t form and, in some cases, can’t survive indefinitely.

    But Kepler gave us more than new exoplanets; it provided a different kind of data. Radial velocity measurements only tell you how much the star is moving, but that motion could be caused by a relatively small planet with an orbital plane aligned with the line of sight from Earth. Or it could be caused by a massive planet with an orbit that’s highly inclined from that line of sight. Physics dictates that, from our perspective, these will produce the same acceleration of the star. Kepler helped us sort out the differences.

    3
    A massive planet orbiting at a steep angle (left) and a small one orbiting at a shallow one will both produce the same motion of a star relative to Earth.

    “Kepler not only found thousands and thousands of exoplanets, but it found them where we know the geometry,” Szentgyorgyi told Ars. “If you know the geometry—if you know the planet transits—you know your orbital inclination is in the plane you’re looking.” This allows follow-on observations using radial velocity to provide a more definitive mass of the exoplanet. Kepler also gave us the radius of each exoplanet.

    “Once you know the mass and radius, you can infer the density,” Szentgyorgyi said. “There’s a remarkable amount of science you can do with that. It doesn’t seem like a lot, but it’s really huge.”

    Density can tell us if a planet is rocky or watery—or whether it’s likely to have a large atmosphere or a small one. Sometimes, it can be tough to tell two possibilities apart; density consistent with a watery world could also be provided by a rocky core and a large atmosphere. But some combinations are either physically implausible or not consistent with planetary formation models, so knowing the density gives us good insight into the planetary type.

    Beyond Kepler

    Despite NASA’s heroic efforts, which kept Kepler going even after its hardware started to fail, its tsunami of discoveries slowed considerably before the decade was over. By that point, however, it had more than done its job. We had a new catalog of thousands of confirmed exoplanets, along with a new picture of our galaxy.

    For instance, binary star systems are common in the Milky Way; we now know that their complicated gravitational environment isn’t a barrier to planet formation.

    We also know that the most common type of star is the low-mass red dwarf. It was previously possible to think that the star’s low mass would be matched by a low-mass planet-forming disk, preventing the generation of large planets and the generation of large families of smaller planets. Neither turned out to be true.

    “We’ve moved into a mode where we can actually say interesting, global, statistical things about exoplanets,” Szentgyorgyi told Ars. “Most exoplanets are small—they’re sort of Earth to sub-Neptune size. It would seem that probably most of the solar-type stars have exoplanets.” And, perhaps most important, there’s a lot of them. “The ubiquity of exoplanets certainly is a stunner… they’re just everywhere,” Szentgyorgyi added.

    That ubiquity has provided the field with two things. First, it has given scientists the confidence to build new equipment, knowing that there are going to be planets to study. The most prominent piece of gear is NASA’s Transiting Exoplanet Survey Satellite, a space-based telescope designed to perform an all-sky exoplanet survey using methods similar to Kepler’s.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    But other projects are smaller, focused on finding exoplanets closer to Earth. If exoplanets are everywhere, they’re also likely to be orbiting stars that are close enough so we can do detailed studies, including characterizing their atmospheres. One famous success in this area came courtesy of the TRAPPIST telescopes [above], which spotted a system hosting at least seven planets. More data should be coming soon, too; on December 17, the European Space Agency launched the first satellite dedicated to studying known exoplanets.

    ESA/CHEOPS

    With future telescopes and associated hardware similar to what Szentgyorgyi is working on, we should be able to characterize the atmospheres of planets out to about 30 light years from Earth. One catch: this method requires that the planet passes in front of its host star from Earth’s point of view.

    When an exoplanet transits in front of its star, most of the light that reaches Earth comes directly to us from the star. But a small percentage passes through the atmosphere of the exoplanet, allowing it to interact with the gases there. The molecules that make up the atmosphere can absorb light of specific wavelengths—essentially causing them to drop out of the light that makes its way to Earth. Thus, the spectrum of the light that we can see using a telescope can contain the signatures of various gases in the exoplanet’s atmosphere.

    There are some important caveats to this method, though. Since the fraction of light that passes through the exoplanet atmosphere is small compared to that which comes directly to us from the star, we have to image multiple transits for the signal to stand out. And the host star has to have a steady output at the wavelengths we’re examining in order to keep its own variability from swamping the exoplanetary signal. Finally, gases in the exoplanet’s atmosphere are constantly in motion, which can make their signals challenging to interpret. (Clouds can also complicate matters.) Still, the approach has been used successfully on a number of exoplanets now.

    In the air

    Understanding atmospheric composition can tell us critical things about an exoplanet. Much of the news about exoplanet discoveries has been driven by what’s called the “habitable zone.” That zone is defined as the orbital region around a star where the amount of light reaching a planet’s surface is sufficient to keep water liquid. Get too close to the star and there’s enough energy reaching the planet to vaporize the water; get too far away and the energy is insufficient to keep water liquid.

    These limits, however, assume an atmosphere that’s effectively transparent at all wavelengths. As we’ve seen in the Solar System, greenhouse gases can play an outsized role in altering the properties of planets like Venus, Earth, and Mars. At the right distance from a star, greenhouse gases can make the difference between a frozen rock and a Venus-like oven. The presence of clouds can also alter a planet’s temperature and can sometimes be identified by imaging the atmosphere. Finally, the reflectivity of a planet’s surface might also influence its temperature.

    The net result is that we don’t know whether any of the planets in a star’s “habitable zone” are actually habitable. But understanding the atmosphere can give us good probabilities, at least.

    The atmosphere can also open a window into the planet’s chemistry and history. On Venus, for example, the huge levels of carbon dioxide and the presence of sulfur dioxide clouds indicate that the planet has an oxidizing environment and that its atmosphere is dominated by volcanic activity. The composition of the gas giants in the outer Solar System likely reflects the gas that was present in the disk that formed the planets early in the Solar System’s history.

    But the most intriguing prospect is that we could find something like Earth, where biological processes produce both methane and the oxygen that ultimately converts it to carbon dioxide. The presence of both in an atmosphere indicates that some process(es) are constantly producing the gases, maintaining a long-term balance. While some geological phenomena can produce both these chemicals, finding them together in an atmosphere would at least be suggestive of possible life.

    Interdisciplinary

    Just the prospect of finding hints of life on other worlds has rapidly transformed the study of exoplanets, since it’s a problem that touches on nearly every area of science. Take the issue of atmospheres and habitability. Even if we understand the composition of a planet’s atmosphere, its temperature won’t just pop out of a simple equation. Distance from the star, type of star, the planet’s rotation, and the circulation of the atmosphere will all play a role in determining conditions. But the climate models that we use to simulate Earth’s atmosphere haven’t been capable of handling anything but the Sun and an Earth-like atmosphere. So extensive work has had to be done to modify them to work with the conditions found elsewhere.

    Similar problems appear everywhere. Geologists and geochemists have to infer likely compositions given little more than a planet’s density and perhaps its atmospheric compositions. Their results need to be combined with atmospheric models to figure out what the surface chemistry of a planet might be. Biologists and biochemists can then take that chemistry and figure out what reactions might be possible there. Meanwhile, the planetary scientists who study our own Solar System can provide insight into how those processes have worked out here.

    “I think it’s part of the Renaissance aspect of exoplanets,” Szentgyorgyi told Ars. “A lot of people now think a lot more broadly, there’s a lot more cross-disciplinary interaction. I find that I’m going to talks about geology, I’m going to talks about the atmospheric chemistry on Titan.”

    The next decade promises incredible progress. A new generation of enormous telescopes is expected to come online, and the James Webb space telescope should devote significant time to imaging exosolar systems.

    NASA/ESA/CSA Webb Telescope annotated


    ____________________________________________
    Other giant 30 meter class telescopes planned

    ESO/E-ELT,39 meter telescope to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    TMT-Thirty Meter Telescope, proposed and now approved for Mauna Kea, Hawaii, USA4,207 m (13,802 ft) above sea level, the only giant 30 meter class telescope for the Northern hemisphere


    ____________________________________________

    We’re likely to end up with much more detailed pictures of some intriguing bodies in our galactic neighborhood.

    The data that will flow from new experiments and new devices will be interpreted by scientists who have already transformed their field. That transformation—from proving that exoplanets exist to establishing a vibrant, multidisciplinary discipline—really took place during the 2010s, which is why it deserves the title “decade of exoplanets.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Ars Technica was founded in 1998 when Founder & Editor-in-Chief Ken Fisher announced his plans for starting a publication devoted to technology that would cater to what he called “alpha geeks”: technologists and IT professionals. Ken’s vision was to build a publication with a simple editorial mission: be “technically savvy, up-to-date, and more fun” than what was currently popular in the space. In the ensuing years, with formidable contributions by a unique editorial staff, Ars Technica became a trusted source for technology news, tech policy analysis, breakdowns of the latest scientific advancements, gadget reviews, software, hardware, and nearly everything else found in between layers of silicon.

    Ars Technica innovates by listening to its core readership. Readers have come to demand devotedness to accuracy and integrity, flanked by a willingness to leave each day’s meaningless, click-bait fodder by the wayside. The result is something unique: the unparalleled marriage of breadth and depth in technology journalism. By 2001, Ars Technica was regularly producing news reports, op-eds, and the like, but the company stood out from the competition by regularly providing long thought-pieces and in-depth explainers.

    And thanks to its readership, Ars Technica also accomplished a number of industry leading moves. In 2001, Ars launched a digital subscription service when such things were non-existent for digital media. Ars was also the first IT publication to begin covering the resurgence of Apple, and the first to draw analytical and cultural ties between the world of high technology and gaming. Ars was also first to begin selling its long form content in digitally distributable forms, such as PDFs and eventually eBooks (again, starting in 2001).

     
  • richardmitnick 6:58 am on December 24, 2019 Permalink | Reply
    Tags: "How 2019’s space missions explored distant worlds", Japan’s Hayabusa2 spacecraft, JAXA’s original Hayabusa spacecraft, , , NASA/MIT TESS, ,   

    From Science News: “How 2019’s space missions explored distant worlds” 

    From Science News

    12.23.19
    Maria Temming

    Planets, asteroids and Arrokoth were the focus of new discoveries.

    1
    Japan’s Hayabusa2 spacecraft, whose shadow is visible in this image, took this photo of the asteroid Ryugu in February after briefly touching down on the asteroid’s surface to collect a sample. The spacecraft is now heading back to Earth.
    JAXA, Univ. of Tokyo, Kochi Univ., Rikkyo Univ., Nagoya Univ., Chiba Inst. Of Technology, Meiji Univ., Univ. of Aizu, AIST

    JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita

    From asteroids to exoplanets, spacecraft are leaving no space rock unturned. While agencies in China, India and Israel made headlines with missions to the moon, here are some other places that space probes scouted in 2019.

    Zoom and enhance

    Touring Pluto in 2015 may have been New Horizons’ main event (SN: 12/26/15, p. 16), but flying by what used to be called Ultima Thule was an awesome encore.

    2
    WORLD LIKE NO OTHER Long out of reach, Pluto came into focus in 2015 with the NASA/Mew Horizons mission.
    JHU-APL, NASA, SwRI


    2
    Arrokoth appears as a ruddy deformed snowman in this composite image acquired by NASA’s New Horizons spacecraft as it sped past on January 1, 2019. NASA gave Ultima Thule a new official name, Arrokoth.
    NASA, Johns Hopkins University Applied Physics Laboratory, Southwest Research Institute, Roman Tkachenko

    I spy exoplanets

    NASA’s Transiting Exoplanet Survey Satellite, or TESS, racked up eight exoplanet finds in its first few months of observation (SN: 2/2/19, p. 12).

    NASA/MIT TESS replaced Kepler in search for exoplanets

    That initial cache included some weirdos, such as a planet that is about as dense as pure water and a “lava world” known as LHS 3844b that sizzles at about 540° Celsius. TESS has since discovered a new type of exoplanet called an ultrahot Neptune, which appears to be a fluffy gas giant in the process of stripping down to its rocky core (SN: 8/31/19, p. 11).

    3
    Among the exoplanets discovered by NASA’s Transiting Exoplanet Survey Satellite, TESS, is LHS 3844b (illustrated), a “lava world” slightly bigger than Earth.TESS/NASA and MIT

    Asteroids to go

    The Japan Aerospace Exploration Agency’s Hayabusa2 is expected to become the second spacecraft ever to bring a bit of asteroid back to Earth, after the original Hayabusa probe returned with a souvenir from the asteroid Itokawa in 2010.

    JAXA’s original Hayabusa spacecraft

    Hayabusa2 touched down on the asteroid Ryugu in February to fetch a sample from the asteroid’s surface (SN Online: 2/22/19). Then, to get a deeper sample, Hayabusa2 fired a copper projectile at Ryugu to punch a crater into the asteroid (SN Online: 4/5/19). The probe then ducked down to snag some rubble excavated from the interior (SN: 8/17/19, p. 14). Scientists won’t know exactly how much of Ryugu was collected until Hayabusa2, which started its journey home on November 13, arrives at Earth in late 2020.

    Another sample-return mission, NASA’s OSIRIS-REx, is still orbiting its asteroid.

    NASA OSIRIS-REx Spacecraft

    When the spacecraft first arrived at Bennu in December 2018, observations unveiled a rugged surface littered with boulders — bad news for a probe designed to navigate more beachlike terrain (SN: 4/13/19, p. 10).

    3
    This mosaic image of asteroid Bennu is composed of 12 PolyCam images collected on Dec. 2 by the OSIRIS-REx spacecraft from a range of 15 miles (24 km). The image was obtained at a 50° phase angle between the spacecraft, asteroid and the Sun, and in it, Bennu spans approximately 1,500 pixels in the camera’s field of view.

    Using OSIRIS-REx’s detailed mapping of Bennu from orbit, NASA selected a site for sample collection in the asteroid’s northern hemisphere (SN Online: 12/12/19). Bits of Bennu, to be returned in 2023, may reveal whether a similar asteroid could have delivered to early Earth a molecular starter pack for life (SN: 1/19/19, p. 20).

    The space probe zipped by this Kuiper Belt object, now called Arrokoth, on New Year’s Day (SN Online: 12/30/18).

    Kuiper Belt. Minor Planet Center

    Scientists were on the edge of their seats as the probe snapped pictures and sent higher- and higher-resolution images over several weeks, revealing the visage of Arrokoth to look like an elongated blob, then a snowman and finally a pair of lumpy pancakes (SN: 3/16/19, p. 15). Uncovering the origins of Arrokoth’s awkward shape may lend insight into the early stages of planet formation (SN: 4/13/19, p. 11).

    Meanwhile, on Mars

    4
    NASA’s Mars InSight mission may have made the first recording of a Marsquake. InSight’s seismometer is covered by the domed shield shown here.JPL-Caltech/NASA

    NASA/Mars InSight Lander

    InSight arrived on the Red Planet in November 2018, and the rookie lander may have already captured the first recording of a Marsquake (SN Online: 4/23/19). Unlike tremors on Earth, underground rumblings on Mars are thought to result from the planet contracting as it cools. Studying such seismic signals could help scientists better understand the structure of Mars’ deep interior.

    While InSight had its ear to the ground, the veteran Curiosity rover was measuring the consistency of a Martian mountain (SN Online: 1/31/19).

    NASA/Mars Curiosity Rover


    As Curiosity scaled Mount Sharp, accelerometer readings indicated surprisingly loose rock beneath the rover’s wheels — suggesting that winds formed the mountain by sweeping sediment into a giant pile.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 12:56 pm on December 9, 2019 Permalink | Reply
    Tags: "Mass-ive Implications for Exoplanetary Atmospheres", , , , , , Measuring planetary masses to some degree of precision., NASA/MIT TESS, The Use of Transmission Spectra   

    From AAS NOVA: “Mass-ive Implications for Exoplanetary Atmospheres” 

    AASNOVA

    From AAS NOVA

    9 December 2019
    Tarini Konchady

    1
    Artist’s impression of an extrasolar planet system. [R. Hurt (IPAC)/NASA/JPL-Caltech]

    One of the goals of the Transiting Exoplanet Survey Satellite (TESS) is to identify exoplanets whose atmospheres can be characterized by other telescopes.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    Part of this process entails measuring planetary masses to some degree of precision. So just how well do we need to know an exoplanet’s mass to understand its atmosphere?

    The Use of Transmission Spectra

    One way to study the atmosphere of an exoplanet is to observe the light from its host star that passes through the planet’s atmosphere. Comparing the resulting spectrum — called a transmission spectrum — with the spectrum of the host star alone can tell us about what’s in the planet’s atmosphere.

    A planet’s mass plays an important role in how far its atmosphere extends. This has prompted studies on whether a planet’s mass could be inferred from its transmission spectrum alone. In some cases, this approach works. But in other cases, the transmission spectra of very different planets can appear to be alike.

    2
    The precision of exoplanet mass measurements versus their most likely mass. The seven planets used in this study are highlighted. [Adapted from Batalha et al. 2019]

    So should we know the mass of a planet before trying to characterize its atmosphere? If so, how well? And how do these answers change for different types of planets? Natasha Batalha (University of California, Santa Cruz) and collaborators attempt to tackle these questions with simulated James Webb Space Telescope (JWST) transmission spectra.

    Seven Special Planets

    For their study, Batalha and collaborators chose seven known planets that span the gamut of exoplanets we’ve observed. Their sample included three hot Jupiters (WASP-17b, HAT-P-1b, WASP-12b), three Neptune-like planets (HAT-P-26 b, GJ 436b, GJ 1214b), and one Earth-like planet (TRAPPIST-1e).

    To simulate transmission spectra, the authors started with models that are consistent with Hubble spectroscopy of their chosen planets. They then used these models to simulate the analogous JWST spectra.

    Aside from mass, the sample planets also varied in composition. Their host stars are also different, meaning that in real life the JWST would have to adopt different observing strategies to get quality transmission spectra.

    4
    The accuracy with which different atmospheric properties are recovered from the simulated transmission spectra. From top left, clockwise: temperature, metallicity (the abundance of elements that are not hydrogen or helium), radius, and mass. The shaded regions correspond to mass being known and the unfilled regions correspond to mass not being known. The colors of the curves indicate different planets. [Batalha et al. 2019]

    A Matter of Caution

    To test what role mass played in the usefulness of transmission spectra, the authors attempted to measure atmospheric properties from their modeled spectra. They tried different precisions on mass (how far off the assumed mass could be from the true mass) as well as not knowing a planet’s mass at all.

    The authors found that transmission spectra alone could not reliably characterize a planet’s atmosphere. Hot Jupiters required the loosest mass constraints to infer atmospheric properties, though cloud cover — such as in the case of WASP-12b — could make that untrue. For the other Neptunes and the Earth-like planet, mass had to be known with at least a 50% precision to get accurate atmospheric properties.

    A recurring theme was that a mass measurement is necessary to distinguish one planet from others with similar transmission spectra. To this end, the authors recommend that any planets selected for atmospheric characterization have their mass known to at least 50% precision.

    One of TESS’s goals is to measure the mass of fifty Earth-sized planets, and Batalha and collaborators have set a benchmark for those measurements. This sort of groundwork is critical to exoplanet science and should contribute to great results not too long from now!

    Citation

    “The Precision of Mass Measurements Required for Robust Atmospheric Characterization of Transiting Exoplanets,” Natasha E. Batalha et al 2019 ApJL 885 L25.
    https://iopscience.iop.org/article/10.3847/2041-8213/ab4909

    See the full article here .
    See also from UCSC “From UC Santa Cruz and Carnegie Institution for Science: “Composition of gas giant planets not determined by host star, study finds”


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

    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 4:54 pm on December 3, 2019 Permalink | Reply
    Tags: "NASA’s Exoplanet-Hunting Mission Catches a Natural Comet Outburst in Unprecedented Detail", , , , , NASA/MIT TESS   

    From NASA/MIT TESS: “NASA’s Exoplanet-Hunting Mission Catches a Natural Comet Outburst in Unprecedented Detail” 

    NASA/MIT TESS replaced Kepler in search for exoplanets

    NASA image
    From NASA/MIT TESS

    Dec. 3, 2019

    Claire Andreoli
    NASA’s Goddard Space Flight Center
    301-286 -1940
    claire.andreoli@nasa.gov

    Matthew Wright
    University of Maryland, College Park
    301-405-9267
    mewright@umd.edu

    Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers at the University of Maryland (UMD), in College Park, Maryland, have captured a clear start-to-finish image sequence of an explosive emission of dust, ice and gases during the close approach of comet 46P/Wirtanen in late 2018. This is the most complete and detailed observation to date of the formation and dissipation of a naturally-occurring comet outburst. The team members reported their results in the November 22 issue of The Astrophysical Journal Letters.

    1
    This animation shows an explosive outburst of dust, ice and gases from comet 46P/Wirtanen that occurred on September 26, 2018 and dissipated over the next 20 days. The images, from NASA’s TESS spacecraft, were taken every three hours during the first three days of the outburst. Credits: Farnham et al./NASA

    “TESS spends nearly a month at a time imaging one portion of the sky. With no day or night breaks and no atmospheric interference, we have a very uniform, long-duration set of observations,” said Tony Farnham, a research scientist in the UMD Department of Astronomy and the lead author of the research paper. “As comets orbit the Sun, they can pass through TESS’ field of view. Wirtanen was a high priority for us because of its close approach in late 2018, so we decided to use its appearance in the TESS images as a test case to see what we could get out of it. We did so and were very surprised!”

    “While TESS is a powerhouse for discovering planets orbiting nearby, bright stars, its observing strategy enables so much exciting additional science,” said TESS project scientist Padi Boyd of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Since the TESS data are rapidly made public through NASA’s Mikulski Archive for Space Telescopes (MAST), it’s exciting to see scientists identifying which data are of interest to them, and then doing all kinds of additional serendipitous science beyond exoplanets.”

    Normal comet activity is driven by sunlight vaporizing the ices near the surface of the nucleus, and the outflowing gases drag dust off the nucleus to form the coma. However, many comets are known to experience occasional spontaneous outbursts that can significantly, but temporarily increase the comet’s activity. It is not currently known what causes outbursts, but they are related to the conditions on the comet’s surface. A number of potential trigger mechanisms have been proposed, including a thermal event, in which a heat wave penetrates into a pocket of highly volatile ices, causing the ice to rapidly vaporize and produce an explosion of activity, and a mechanical event, where a cliff collapses, exposing fresh ice to direct sunlight. Thus, studies of the outburst behavior, especially in the early brightening stages that are difficult to capture, can help us understand the physical and thermal properties of the comet.

    Although Wirtanen came closest to Earth on December 16, 2018, the outburst occurred earlier in its approach, beginning on September 26, 2018. The initial brightening of the outburst occurred in two distinct phases, with an hour-long flash followed by a more gradual second stage that continued to grow brighter for another 8 hours. This second stage was likely caused by the gradual spreading of comet dust from the outburst, which causes the dust cloud to reflect more sunlight overall. After reaching peak brightness, the comet faded gradually over a period of more than two weeks. Because TESS takes detailed, composite images every 30 minutes, the team was able to view each phase in exquisite detail.

    “With 20 days’ worth of very frequent images, we were able to assess changes in brightness very easily. That’s what TESS was designed for, to perform its primary job as an exoplanet surveyor,” Farnham said. “We can’t predict when comet outbursts will happen. But even if we somehow had the opportunity to schedule these observations, we couldn’t have done any better in terms of timing. The outburst happened mere days after the observations started.”

    The team has generated a rough estimate of how much material may have been ejected in the outburst, about one million kilograms (2.2 million pounds), which could have left a crater on the comet of around 20 meters (about 65 feet) across. Further analysis of the estimated particle sizes in the dust tail may help improve this estimate. Observing more comets will also help to determine whether multi-stage brightening is rare or commonplace in comet outbursts.

    TESS has also detected for the first time Wirtanen’s dust trail. Unlike a comet’s tail—the spray of gas and fine dust that follows behind a comet, growing as it approaches the sun—a comet’s trail is a field of larger debris that traces the comet’s orbital path as it travels around the sun. Unlike a tail, which changes direction as it is blown by the solar wind, the orientation of the trail stays more or less constant over time.

    “The trail more closely follows the orbit of the comet, while the tail is offset from it, as it gets pushed around by the sun’s radiation pressure. What’s significant about the trail is that it contains the largest material,” said Michael Kelley, an associate research scientist in the UMD Department of Astronomy and a co-author of the research paper. “Tail dust is very fine, a lot like smoke. But trail dust is much larger—more like sand and pebbles. We think comets lose most of their mass through their dust trails. When the Earth runs into a comet’s dust trail, we get meteor showers.”

    While the current study describes initial results, Farnham, Kelley and their colleagues look forward to further analyses of Wirtanen, as well as other comets in TESS’ field of view. “We also don’t know what causes natural outbursts and that’s ultimately what we want to find,” Farnham said. “There are at least four other comets in the same area of the sky where TESS made these observations, with a total of about 50 comets expected in the first two years’ worth of TESS data. There’s a lot that can come of these data.”

    For an image, refer to: https://www.nasa.gov/feature/goddard/2019/tess-comet-outburst

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The 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.

     
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