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

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

    ESA Space For Europe Banner

    European Space Agency

    20 March 2018

    Markus Bauer








    ESA Science Communication Officer









    Tel: +31 71 565 6799









    Mob: +31 61 594 3 954









    Email: markus.bauer@esa.int

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    Hot exoplanet.

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

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

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    ESA Ariel spacecraft.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    NASA/ESA Solar Orbiter

    ESA/Euclid spacecraft

    ESA/PLATO

    See the full article here .

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

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

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

    U Cambridge bloc

    University of Cambridge

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

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

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

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

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

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

    NASA/Chandra Telescope

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

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

    See the full article here .

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    U Cambridge Campus

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

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

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

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

    NASA Kepler Logo

    NASA Kepler Telescope
    NASA/Kepler

    12.14.17

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

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

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

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

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

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


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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    See the full article here .

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

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

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

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  • richardmitnick 10:08 am on December 6, 2017 Permalink | Reply
    Tags: , , , , Exoplanet research, Red-dwarf star k2-18 with exoplanets K2-18b and its neighbour newly discovered K2-18c,   

    From Universe Today: “Two new Super-Earths Discovered Around a Red Dwarf Star” 

    universe-today

    Universe Today

    5 Dec , 2017
    Matt Williams

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    K2-18b and its neighbour, newly discovered K2-18c, orbit the red-dwarf star k2-18 locataed 111 light years away in the constellation Leo. Credit: Alex Boersma

    The search for extra-solar planets has turned up some very interesting discoveries. Aside planets that are more-massive versions of their Solar counterparts (aka. Super-Jupiters and Super-Earths), there have been plenty of planets that straddle the line between classifications. And then there were times when follow-up observations have led to the discovery of multiple planetary systems.

    This was certainly the case when it came to K2-18, a red dwarf star system located about 111 light-years from Earth in the constellation Leo. Using the ESO’s High Accuracy Radial Velocity Planet Searcher (HARPS), an international team of astronomers was recently examining a previously-discovered exoplanet in this system (K2-18b) when they noted the existence of a second exoplanet.

    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO/HARPS at La Silla

    The study which details their findings – Characterization of the K2-18 multi-planetary system with HARPS – is scheduled to be published in the journal Astronomy and Astrophysics. The research was supported by the Natural Sciences and Research Council of Canada (NSERC) and the Institute for Research on Exoplanets – a consortium of scientists and students from the University of Montreal and McGill University.

    See the full article here .

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  • richardmitnick 4:06 pm on December 4, 2017 Permalink | Reply
    Tags: A New Spin to Solving Mystery of Stellar Companions, Are these planetary-mass companions actually planets or are they instead small "failed" stars called brown dwarfs?, , , , , , Exoplanet research, , These new spin measurements suggest that if these bodies are massive planets located far away from their stars they have properties that are very similar to those of the smallest brown dwarfs   

    From Keck: “A New Spin to Solving Mystery of Stellar Companions” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    December 4, 2017
    Mari-Ela Chock, Keck Observatory
    (808) 554-0567
    mchock@keck.hawaii.edu

    Whitney Clavin, Caltech
    (626) 395-1856
    wclavin@caltech.edu

    1
    Credit: Gauza, B. et al 2015, MNRAS, 452, 1677-1683
    Image of the planetary-mass companion VHS 1256-1257 b (bottom right) and its host star (center).

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    Credit: Ireland, M. J. et al 2011, ApJ, 726, 113
    Image of the planetary-mass companion GSC 6214-210 b (bottom) and its host star (top).

    3
    Credit: Kraus, A. L. et al. 2014, ApJ, 781, 20
    Image of the planetary-mass companion ROXs 42B b (right, labeled ‘b’) and its host star (left, labeled ‘A’).

    Researchers Measure the Spin Rates of Bodies Thought to be Either Planets or Tiny “Failed” Stars.

    Taking a picture of an exoplanet—a planet in a solar system beyond our sun—is no easy task. The light of a planet’s parent star far outshines the light from the planet itself, making the planet difficult to see. While taking a picture of a small rocky planet like Earth is still not feasible, researchers have made strides by snapping images of about 20 giant planet-like bodies. These objects, known as planetary-mass companions, are more massive than Jupiter, orbit far from the glare of their stars, and are young enough to still glow with heat from their formation—all traits that make them easier to photograph.

    But one big question remains: Are these planetary-mass companions actually planets, or are they instead small “failed” stars called brown dwarfs? Brown dwarfs form like stars do—out of collapsing clouds of gas—but they lack the mass to ignite and shine with starlight. They can be found floating on the their own in space, or they can be found orbiting with other brown dwarfs or stars. The smallest brown dwarfs are similar in size to Jupiter and would look just like a planet when orbiting a star.

    Using the W. M. Keck Observatory on Maunakea, Hawaii, researchers at Caltech have taken a new approach to the mystery: they have measured the spin rates of three of the photographed planetary-mass companions and compared them to spin rates for small brown dwarfs. The results offer a new set of clues that hint at how the companions may have formed.

    “These companions with their high masses and wide separations could have formed either as planets or brown dwarfs,” says graduate student Marta Bryan (MS ’14), lead author of a new study describing the findings in the journal Nature Astronomy . “In this study, we wanted to shed light on their origins.”

    “These new spin measurements suggest that if these bodies are massive planets located far away from their stars, they have properties that are very similar to those of the smallest brown dwarfs,” says Heather Knutson, professor of planetary science at Caltech and a co-author of the paper.

    The astronomers measured the spin rate, or the length of a day, of three planetary-mass companions known as ROXs 42B b, GSC 6214-210 b, and VHS 1256-1257 b. They used an instrument at Keck Observatory called the Near Infrared Spectrograph (NIRSpec) to dissect the light coming from the companions.

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    Keck NIRSpec schematic

    As the objects spin on their axes, light from the side that is turning toward us shifts to shorter, bluer wavelengths, while light from the receding side shifts to longer, redder wavelengths. The degree of this shifting indicates the speed of a rotating body. The results showed that the three companions’ spin rates ranged between six to 14 kilometers per second, similar to rotation rates of our solar system’s gas giant planets Saturn and Jupiter.

    For the study, the researchers also included the two planetary-mass companions for which spin rates had already been measured. One, β Pictoris b, has a rotation rate of 25 kilometers per second—the fastest rotation rate of any planetary-mass body measured so far.

    The researchers compared the spin rates for the five companions to those measured previously for small free-floating brown dwarfs. The ranges of rotation rates for the two populations were indistinguishable. In other words, the companions are whirling about their own axes at about the same speeds as their free-floating brown-dwarf counterparts.

    The results suggest two possibilities. One is that the planetary-mass companions are actually brown dwarfs. The second possibility is that the companions looked at in this study are planets that formed, just as planets do, out of disks of material swirling around their stars, but for reasons not yet understood, the objects ended up with spin rates similar to those of brown dwarfs. Some researchers think that both newly forming planets and brown dwarfs are encircled by miniature gas disks that might be helping to slow their spin rates. In other words, similar physical processes may leave planets and brown dwarfs with similar spin rates.

    “It’s a question of nature versus nurture,” says Knutson. “Were the planetary companions born like brown dwarfs, or did they just end up behaving like them with similar spins?”

    The team also says that the companions are spinning more slowly than expected. Growing planets tend to be spun up by the material they pull in from a surrounding gas disk, in the same way that spinning ice skaters increase their speed, or angular momentum, when they pull their arms in. The relatively slow rotation rates observed for these objects indicate that they were able to effectively put the brakes on this spin-up process, perhaps by transferring some of this angular momentum back to encircling gas disks. The researchers are planning future studies of spin rates to further investigate the matter.

    “Spin rates of planetary-mass bodies outside our solar system have not been fully explored,” says Bryan. “We are just now beginning to use this as a tool for understanding formation histories of planetary-mass objects.”

    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 3:01 pm on December 4, 2017 Permalink | Reply
    Tags: Airapetian and Goddard colleague William Danchi argue the solar flares were an essential part of the process that led to us, As a way to potentially improve the chances of finding habitable conditions on those exoplanets that are observed a new approach has been proposed by a group of NASA scientists, , , , , , Exoplanet research, , , The novel technique takes advantage of the frequent stellar storms emanating from cool young dwarf stars, This new research suggests that some stellar storms could have just the opposite effect — making the planet more habitable., When high-energy particles from a stellar storm reach an exoplanet they break the nitrogen oxygen and water molecules that may be in the atmosphere into their individual components   

    From Many Worlds: “A New Way to Find Signals of Habitable Exoplanets?” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-12-04
    Marc Kaufman

    1
    Scientists propose a new and more indirect way of determining whether an exoplanet has a good, bad or unknowable chance of being habitable. (NASA’s Goddard Space Flight Center/Mary Pat Hrybyk)

    The search for biosignatures in the atmospheres of distant exoplanets is extremely difficult and time-consuming work. The telescopes that can potentially take the measurements required are few and more will come only slowly. And for the current and next generation of observatories, staring at a single exoplanet long enough to get a measurement of the compounds in its atmosphere will be a time-consuming and expensive process — and thus a relatively infrequent one.

    As a way to potentially improve the chances of finding habitable conditions on those exoplanets that are observed, a new approach has been proposed by a group of NASA scientists.

    The novel technique takes advantage of the frequent stellar storms emanating from cool, young dwarf stars. These storms throw huge clouds of stellar material and radiation into space – traveling near the speed of light — and the high energy particles then interact with exoplanet atmospheres and produce chemical biosignatures that can be detected.

    The study, titled “Atmospheric Beacons of Life from Exoplanets Around G and K Stars“, recently appeared in Nature Scientific Reports.

    “We’re in search of molecules formed from fundamental prerequisites to life — specifically molecular nitrogen, which is 78 percent of our atmosphere,” said Airapetian, who is a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and at American University in Washington, D.C. “These are basic molecules that are biologically friendly and have strong infrared emitting power, increasing our chance of detecting them.”

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    The thin gauzy rim of the planet in foreground is an illustration of its atmosphere. (NASA’s Goddard Space Flight Center)

    So this technique, called a search for “Beacons of Life,” would not detect signs of life per se, but would detect secondary or tertiary signals that would, in effect, tell observers to “look here.”

    The scientific logic is as follows:

    When high-energy particles from a stellar storm reach an exoplanet, they break the nitrogen, oxygen and water molecules that may be in the atmosphere into their individual components.

    Water molecules become hydroxyl — one atom each of oxygen and hydrogen, bound together. This sparks a cascade of chemical reactions that ultimately produce what the scientists call the atmospheric beacons of hydroxyl, more molecular oxygen, and nitric oxide.

    For researchers, these chemical reactions are very useful guides. When starlight strikes the atmosphere, spring-like bonds within the beacon molecules absorb the energy and vibrate, sending that energy back into space as heat, or infrared radiation. Scientists know which gases emit radiation at particular wavelengths of light. So by looking at all the radiation coming from the that planet’s atmosphere, it’s possible to get a sense of what chemicals are present and roughly in what amounts..

    Forming a detectable amount of these beacons requires a large quantity of molecular oxygen and nitrogen. As a result, if detected these compounds would suggest the planet has an atmosphere filled with biologically friendly chemistry as well as Earth-like atmospheric pressure. The odds of the planet being a habitable world remain small, but those odds do grow.

    “These conditions are not life, but are fundamental prerequisites for life and are comparable to our Earth’s atmosphere,” Airapetian wrote in an email.

    Stellar storms and related coronal mass ejections are thought to burst into space when magnetic reconnections in various regions of the star. For stars like our sun, the storms become less frequent within a relatively short period, astronomically speaking. Smaller and less luminous red dwarf stars, which are the most common in the universe, continue to send out intense stellar flares for a much longer time.

    3
    Vladimir Airapetian is a senior researcher at NASA Goddard and a member of NASA’s Nexus for Exoplanet System Science (NExSS) initiative.

    The effect of stellar weather on planets orbiting young stars, including our own four billion years ago, has been a focus of Airapetian’s work for some time.

    For instance, Airapetian and Goddard colleague William Danchi published a paper in the journal Nature last year proposing that solar flares warmed the early Earth to make it habitable. They concluded that the high-energy particles also provided the vast amounts of energy needed to combine evenly scattered simple molecules into the kind of complex molecules that could keep the planet warm and form some of the chemical building blocks of life.

    In other words, they argue, the solar flares were an essential part of the process that led to us.

    What Airapetian is proposing now is to look at the chemical results of stellar flares hitting exoplanet atmospheres to see if they might be an essential part of a life-producing process as well, or of a process that creates a potentially habitable planet.

    Airapetian said that he is again working with Danchi, a Goddard astrophysicist, and the team from heliophysics to propose a NASA mission that would use some of their solar and stellar flare findings. The mission being conceived, the Exo Life Beacon Space Telescope (ELBST), would measure infrared emissions of an exoplanet atmosphere using direct imaging observations, along with technology to block the infrared emissions of the host star.

    For this latest paper, Airapetian and colleagues used a computer simulation to study the interaction between the atmosphere and high-energy space weather around a cool, active star. They found that ozone drops to a minimum and that the decline reflects the production of atmospheric beacons.

    They then used a model to calculate just how much nitric oxide and hydroxyl would form and how much ozone would be destroyed in an Earth-like atmosphere around an active star. Earth scientists have used this model for decades to study how ozone — which forms naturally when sunlight strikes oxygenin the upper atmosphere — responds to solar storms. But the ozone reactions found a new application in this study; Earth is, after all, the best case study in the search for habitable planets and life.

    Will this new approach to searching for habitable planets out?

    “This is an exciting new proposed way to look for life,” said Shawn Domagal-Goldman, a Goddard astrobiologist not connected with the study. “But as with all signs of life, the exoplanet community needs to think hard about context. What are the ways non-biological processes could mimic this signature?”

    4
    A 2012 coronal mass ejection from the sun. Earth is placed into the image to give a sense of the size of the solar flare, but our planet is of course nowhere near the sun. (NASA, Goddard Media Studios)

    Today, Earth enjoys a layer of protection from the high-energy particles of solar storms due to its strong magnetic field. However, some particularly strong solar events can still interact with the magnetosphere and potentially wreak havoc on certain technology on Earth.

    The National Oceanic and Atmospheric Administration classifies solar storms on a scale of one to five (one being the weakest; five being the most severe). For instance, a storm forecast to be a G3 event means it could have the strength to cause fluctuations in some power grids, intermittent radio blackouts in higher latitudes and possible GPS issues.

    This is what can happen to a planet with a strong magnetic field and a sun that is no longer prone to sending out frequent solar flares. Imagine what stellar storms can do when the star is younger and more prone to powerful flaring, and the planet less protected.

    Exoplanet scientists often talk of the possibility that a particular planet was “sterilized” by the high-energy storms, and so could never be habitable. But this new research suggests that some stellar storms could have just the opposite effect — making the planet more habitable.

    See the full article here.

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    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

     
  • richardmitnick 12:02 pm on September 19, 2017 Permalink | Reply
    Tags: , Exoplanet research, To find aliens, we must think of life as we don’t know it   

    From aeon: “To find aliens, we must think of life as we don’t know it” 

    1

    aeon

    9.19.17
    Ramin Skibba

    1
    Jupiter’s moon, Europa, is believed to conceal a buried ocean. Photo NASA/JPL-Caltech/SETI Institute

    From blob-like jellyfish to rock-like lichens, our planet teems with such diversity of life that it is difficult to recognise some organisms as even being alive. That complexity hints at the challenge of searching for life as we don’t know it – the alien biology that might have taken hold on other planets, where conditions could be unlike anything we’ve seen before. ‘The Universe is a really big place. Chances are, if we can imagine it, it’s probably out there on a planet somewhere,’ said Morgan Cable, an astrochemist at the Jet Propulsion Laboratory in Pasadena, California. ‘The question is, will we be able to find it?’

    For decades, astronomers have come at that question by confining their search to organisms broadly similar to the ones here. In 1976, NASA’s Viking landers examined soil samples on Mars, and tried to animate them using the kind of organic nutrients that Earth microbes like, with inconclusive results.

    NASA/Viking 1 Lander

    Later this year, the European Space Agency’s ExoMars Trace Gas Orbiter will begin scoping out methane in the Martian atmosphere, which could be produced by Earth-like bacterial life.

    ESA/ExoMars Trace Gas Orbiter


    ESA/ExoMars

    NASA’s Mars 2020 rover will likewise scan for carbon-based compounds from possible past or present Mars organisms.

    NASA Mars 2020 orbiter schematic

    3
    NASA Mars 2020 rover depiction

    But the environment on Mars isn’t much like that on Earth, and the exoplanets that astronomers are finding around other stars are stranger still – many of them quite unlike anything in our solar system. For that reason, it’s important to broaden the search for life. We need to open our minds to genuinely alien kinds of biological, chemical, geological and physical processes. ‘Everybody looks for “biosignatures”, but they’re meaningless because we don’t have any other examples of biology,’ said the chemist Lee Cronin at the University of Glasgow.

    To open our minds, we need to go back to basics and consider the fundamental conditions that are necessary for life. First, it needs some form of energy, such as from volcanic hot springs or hydrothermal vents. That would seem to rule out any planets or moons lacking a strong source of internal heat. Life also needs protection from space radiation, such as an atmospheric ozone layer. Many newly discovered Earth-size worlds, including ones around TRAPPIST-1 and Proxima Centauri, orbit red dwarf stars whose powerful flares could strip away a planet’s atmosphere.

    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 interior

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

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    Studies by the James Webb Space Telescope (JWST), set to launch next year, will reveal whether we should rule out these worlds, too.

    NASA/ESA/CSA Webb Telescope annotated

    Finally, everything we know about life indicates that it requires some kind of liquid solvent in which chemical interactions can lead to self-replicating molecules. Water is exceptionally effective in that regard. It facilitates making and breaking chemical bonds, assembling proteins or other structural molecules, and – for an actual organism – feeding and getting rid of waste. That’s why planetary scientists currently focus on the ‘habitable zone’ around stars, the locations where a world could have the right temperature for liquid water on its surface.

    These constraints still leave a bewildering range of possibilities. Perhaps other liquids could take the place of water. Or a less exotic possibility: maybe biology could arise in the buried ocean on an ice-covered alien world. Such a setting could offer energy, protection and liquid water, yet provide almost no outward sign of life, making it tough to detect. For planets around other stars, we simply do not know enough yet to say what is (or is not) happening there. ‘It’s difficult to imagine that we could definitively find life on an exoplanet,’ conceded Jonathan Lunine, a planetary scientist at Cornell University. ‘But the outer solar system is accessible to us.’

    The search for exotic life therefore must begin close to home. The moons of Saturn and Jupiter offer a test case of whether biology could exist without an atmosphere. Jupiter’s Europa and Saturn’s Enceladus both have inner oceans and internal heat sources. Enceladus spews huge geysers of water vapour from its south pole; Europa appears to puff off occasional plumes as well. Future space missions could fly through the plumes and study them for possible biochemicals. NASA’s proposed Europa lander, which could launch in about a decade, could seek out possible microbe-laced ocean water that seeped up or snowed back down onto the surface.

    3
    An artist’s concept of a Europa lander, which would look for evidence of past or present life on the icy moon of Jupiter during a 20-day mission on the surface. Credit: NASA/JPL-Caltech

    Meanwhile, another Saturn moon, Titan, could tell us whether life can arise without liquid water. Titan is dotted with lakes of methane and ethane, filled by a seasonal hydrocarbon rain. Lunine and his colleagues have speculated that life could arise in this frigid setting. Several well-formulated (but as-yet unfunded) concepts exist for a lander that could investigate Titan’s methane lakes, looking for microbial life.

    For the motley bunch of exoplanets that have no analog in our solar system, however, scientists have to rely on laboratory experiments and sheer imagination. ‘We’re still looking for the basic physical and chemical requirements that we think life needs, but we’re trying to keep the net as broad as possible,’ Cable said. Exoplanet researchers such as Sara Seager at the Massachusetts Institute of Technology and Victoria Meadows at the University of Washington are modelling disparate types of possible planetary atmospheres and the kinds of chemical signatures that life might imprint onto them.

    Now the onus is on NASA and other space agencies to design instruments capable of detecting as many signs of life as possible. Most current telescopes access only a limited range of wavelengths. ‘If you think of the spectrum like a set of venetian blinds, there are only a few slats removed. That’s not a very good way to get at the composition,’ Lunine said. In response, astronomers led by Seager and Scott Gaudi of the Ohio State University have proposed the Habitable Exoplanet Imaging Mission (HabEx) for NASA in the 2030s or 2040s. It would scan exoplanets over a wide range of optical and near-infrared wavelengths for signs of oxygen and water vapour.

    Casting a wide search for ET won’t be easy and it won’t be cheap, but it will surely be transformative. Even if astrobiologists find nothing, that knowledge will tell us how special life is here on Earth. And any kind of success will be Earth-shattering. Finding terrestrial-style bacteria on Mars would tell us we’re not alone. Finding methane-swimming organisms on Titan would tell us, even more profoundly, that ours is not the only way to make life. Either way, we Earthlings will never look at the cosmos the same way again.

    See the full article here .

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    Since 2012, Aeon has established itself as a unique digital magazine, publishing some of the most profound and provocative thinking on the web. We ask the big questions and find the freshest, most original answers, provided by leading thinkers on science, philosophy, society and the arts.

    Aeon has three channels, and all are completely free to enjoy:

    Essays – Longform explorations of deep issues written by serious and creative thinkers

    Ideas – Short provocations, maintaining Aeon’s high editorial standards but in a more nimble and immediate form. Our Ideas are published under a Creative Commons licence, making them available for republication.

    Video – A mixture of curated short documentaries and original Aeon productions

    Through our Partnership program, we publish pieces from university research groups, university presses and other selected cultural organisations.

    Aeon was founded in London by Paul and Brigid Hains. It now has offices in London, Melbourne and New York. We are a not-for-profit, registered charity operated by Aeon Media Group Ltd. Aeon is endorsed as a Deductible Gift Recipient (DGR) organisation in Australia and, through its affiliate Aeon America, registered as a 501(c)(3) charity in the US.

    We are committed to big ideas, serious enquiry and a humane worldview. That’s it.

     
  • richardmitnick 4:20 am on August 10, 2017 Permalink | Reply
    Tags: , , , , ESO/HARPS, Exoplanet research, , , Tau Ceti, U Hertfordshire   

    From Keck Observatory: “Four Earth-Sized Planets Found Orbiting the Nearest Sun-Like Star” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    August 9, 2017
    MEDIA CONTACT:
    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567
    mchock@keck.hawaii.edu

    1
    This illustration compares the four planets detected around the nearby star Tau Ceti (top) and the inner planets of our solar system (bottom). Credit: CREDIT: F. FENG, UNIVERSITY OF HERTFORDSHIRE, UNITED KINGDOM

    A new study by an international team of astronomers reveals that Tau Ceti, the nearest Sun-like star about 12 light years away from the Sun, has four Earth-sized planets orbiting it.

    These planets have masses as low as 1.7 Earth mass, making them among the smallest planets ever detected around the nearest Sun-like stars. Two of them are Super-Earths located in the habitable zone of the star and thus could support liquid surface water.

    The data were obtained by using the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph at the European Southern Observatory in Chile, combined with the High-Resolution Echelle Spectrometer (HIRES) at the W. M. Keck Observatory on Maunakea, Hawaii.

    ESO/HARPS at La Silla

    ESO 3.6m telescope & HARPS at LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    Keck HIRES

    “HIRES is one of only a few spectrometers in the world that have routinely delivered the level of radial velocity precision needed for this kind of work,” said co-author Dr. Steve Vogt, professor of astronomy and astrophysics at University of California, Santa Cruz. “And it is one of only two instruments in the world, the other being HARPS, that has been able to deliver this precision level for over a decade. It is a very unique facility in the exoplanet discovery field.”

    The four planets were detected by observing the wobbles in the movement of Tau Ceti. This wobble, known as the Doppler effect, happens when a planet’s gravity slightly tugs at its host star as it orbits.

    Measuring Tau Ceti’s wobbles required techniques sensitive enough to detect variations in its movement as small as 30 centimeters per second. The smaller the planet, the weaker its gravitational pull on its host star, and the harder it is to detect the star’s wobble.

    “We are getting tantalizingly close to the 10 centimeters per second limit required for detecting Earth analogs,” said Dr. Fabo Feng from the University of Hertfordshire in the United Kingdom and lead author of the study. “Our detection of such weak wobbles is a milestone in the search for Earth analogs and the understanding of the Earth’s habitability through comparison with these analogs.”

    The outer two planets around Tau Ceti are likely to be candidate habitable worlds, although a massive debris disc around the star probably reduces their habitability due to intensive bombardment by asteroids and comets.

    The same team also investigated Tau Ceti four years ago in 2013, when Dr. Mikko Tuomi led an effort in developing data analysis techniques and used the star as a benchmark case.

    “We came up with an ingenious way of telling the difference between signals caused by planets and those caused by a star’s activity. We realized that we could see how a star’s activity differed at different wavelengths, then used that information to separate this activity from signals of planets,” said Dr. Tuomi.

    “We have painstakingly improved the sensitivity of our techniques and could rule out two of the signals our team identified in 2013 as planets. But no matter how we look at the star, there seems to be at least four rocky planets orbiting it,” Dr. Tuomi added. “We are slowly learning to tell the difference between wobbles caused by planets and those caused by stellar active surface. This enabled us to essentially verify the existence of the two outer, potentially habitable, planets in the system.”

    Sun-like stars are thought to be the best targets for searching for habitable Earth-sized planets due to their similarity to the Sun. Unlike more common smaller stars such as the red dwarf stars Proxima Centauri and Trappist-1, they are not so faint that planets would be tidally locked, showing the same side to the star at all times.

    Tau Ceti is very similar to the Sun in its size and brightness, and they both host multi-planet systems. If the outer two planets are found to be habitable, Tau Ceti could be an optimal target for interstellar colonization, as seen in science fiction.

    “Such weak signals of planets almost the size of the Earth cannot be seen without using advanced statistical and modeling approaches. We have introduced new methods to remove the noise in the data in order to reveal the weak planetary signals,” said Dr. Feng.

    About HIRES

    The High-Resolution Echelle Spectrometer (HIRES) produces spectra of single objects at very high spectral resolution, yet covering a wide wavelength range. It does this by separating the light into many “stripes” of spectra stacked across a mosaic of three large CCD detectors. HIRES is famous for finding planets orbiting other stars. Astronomers also use HIRES to study distant galaxies and quasars, finding clues to the Big Bang.

    Science paper:
    Color difference makes a difference: four planet candidates around tau Ceti, The Astrophysical Journal.

    Authors

    Fabo Feng, Mikko Tuomi, Hugh Jones – University of Hertfordshire, UK
    John Barnes – The Open University, UK
    Guillem Anglada-Escude – Queen Mary University ofLondon, UK
    Steve Vogt – University of California at Santa Cruz, USA
    Paul Butler – Carnegie Institute of Washington, USA

    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

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    Keck Caltech

     
  • richardmitnick 1:28 pm on July 10, 2017 Permalink | Reply
    Tags: , , , , , Exoplanet research, IAC80 and SONG telescopes, , , , NITES   

    From astrobites: “Finding the Brightest Exoplanet Hosts with MASCARA” 

    Astrobites bloc

    Astrobites

    Title: MASCARA-2 b: A hot Jupiter transiting a mV=7.6 A-star
    Authors: G.J.J. Talens, A. B. Justesen, S. Albrecht, et al.
    First Author’s Institution: Leiden Observatory, Leiden University, the Netherlands

    Leiden Observatory


    Status: Submitted to A&A, open access

    Before we start: the system discussed in this astrobite was discovered separately by two teams and presented simultaneously. The other paper, by the KELT team, can be found here. This astrobite will focus on the results of the MASCARA team.


    The MASCARA instrument on La Palma

    Kelt North Telescope In Arizona at Winer Observatory by Ohio State University

    KELT South robotic telescope, Southerland, South Africa

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    Figure 1: The Leiden MASCARA instrument on La Palma. Source: http://mascara.strw.leidenuniv.nl/technical/

    It’s clear that there are a lot of exoplanets out there. While large surveys like K2 continue to bring in hundreds of new planets, other projects are filling in the gaps that these surveys miss.

    NASA/Kepler Telescope

    The relatively new project MASCARA intends to find planets around the brightest host stars yet. They are targeting stars with magnitudes less than 8.4 (remember that fainter stars have higher magnitudes). For comparison, that’s still fainter than the human eye can see (magnitude 6 or less), but it’s a fair bit brighter than the Kepler space telescope can see (Kepler saturates on stars brighter than about 11th magnitude). There are currently only 14 exoplanet host stars known that are brighter than 8.4th magnitude, with the brightest being KELT-9 at a magnitude of 7.56. These exoplanets around bright stars are interesting because it’s so much easier to do follow-up observations on them. In particular, in-depth studies of exoplanet atmospheres — which require collecting starlight that has passed through the exoplanet atmosphere, and studying how the atmosphere has affected the starlight — are much easier when the exoplanet orbits bright stars like these, simply because there are so many more photons that reach us.

    The MASCARA team operate a station at the La Palma observatory in Spain, observing the northern sky. Like many astronomical acronyms, MASCARA takes a bit of imagination: it stands for the Multi-site All-Sky CAmeRA. The station consists of five cameras, one each pointing North, South, East and West, and the fifth pointing straight up. Between them they can cover the whole visible sky. The cameras remain motionless while the stars pass overhead. Like Kepler, MASCARA is looking for exoplanet transits — the dip in a star’s light that means a planet is passing between us and the star. To do this, they take a series of six-second images with each camera. By identifying the same stars between images, and taking into account any atmospheric effects such as passing clouds, they can search each star for dips in brightness that might be exoplanet transits.

    Planet transit. NASA/Ames

    MASCARA-2b [No image available]

    MASCARA-2b is the second exoplanet to be discovered by this method, but the first to be published (MASCARA-1b is also in the works, but 2b was pushed ahead in the queue because of a simultaneous discovery by another team). From the MASCARA data in Figure 2, a clear transit can be seen every 3.47 days. To follow this up, the team observed transits with the NITES, IAC80 and SONG telescopes.

    6
    Near Infra-red Transiting ExoplanetS (NITES) telescope is 0.4-m semi-robotic telescope located at El Observatorio del Roque de los Muchachos (ORM) on La Palma in the Canary Islands

    3
    The IAC 80 telescope of the Observatorio del Teide.

    4
    Danish led SONG telescope i the Canary Islands, Spain.

    To emphasise how bright this star is compared to the usual astronomical targets: these are small telescopes — NITES in particular is only 40cm in diameter. Even these telescopes however had to be kept deliberately out-of-focus, blurring the resulting image and spreading the star’s light over more pixels, because otherwise there would be a danger of saturating the image. This practise is not uncommon for larger telescopes, but it’s surprising to see it necessary on these rather smaller telescopes.

    6
    Figure 2: Searching for strong periods in the MASCARA data (top) and then wrapping data around on that period to see the transit shape (bottom). This is Figure 1 in today’s paper.

    3
    Figure 3: Transits observed with MASCARA (top), NITES (middle) and IAC80 (bottom). Source: Figure 2 in today’s paper.

    The host star has a magnitude of 7.58, narrowly missing the record. It’s also an A-type star, towards the hotter end of the spectrum, and as such the star spins on its axis faster than the average star does. Generally fast rotation makes spectroscopic measurements difficult, as the difference Doppler shift between opposite sides of the star smears out the spectral lines that we’re interested in. Aided by the system’s brightness, however, the team were able to obtain spectra that were high-enough quality to overcome this difficulty. They found that the planet is a hot Jupiter, orbiting at around 6% of the Earth-Sun separation, and that it has a radius around double that of Jupiter itself. They also found that the planet’s orbit is quite well aligned with the direction that the star spins — this is unusual for hot Jupiters in systems like this, which generally seem to orbit with a slight tilt. The team hope that the system is well-placed for follow-up studies of the planet’s atmosphere, adding to the fairly small pool of planets in which such studies are possible.

    The MASCARA team is currently building a second MASCARA instrument in Chile, where it will be able to explore the southern sky — at present, only two of the fourteen brightest exoplanet hosts are southern. This same planet was simultaneously discovered by KELT, another project exploring the same types of stars. This is a growing area of exoplanet research, so look for further interesting results in the future!

    To emphasise how bright this star is compared to the usual astronomical targets: these are small telescopes — NITES in particular is only 40cm in diameter. Even these telescopes however had to be kept deliberately out-of-focus, blurring the resulting image and spreading the star’s light over more pixels, because otherwise there would be a danger of saturating the image. This practise is not uncommon for larger telescopes, but it’s surprising to see it necessary on these rather smaller telescopes.

    See the full article here .

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    What do we do?

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

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

     
  • richardmitnick 12:55 pm on July 6, 2017 Permalink | Reply
    Tags: , , , , , Exoplanet research   

    From ESO: “ESO’s SPHERE Unveils its First Exoplanet” 

    ESO 50 Large

    European Southern Observatory

    6 July 2017
    Gaël Chauvin
    Institut de Planetologie et d’Astrophysique de Grenoble (IPAG)
    BP 53, 38041 Grenoble Cedex 9, France
    +33 6 4551 8209
    gael.chauvin@univ-grenoble-alpes.fr

    Jean-Luc Beuzit
    Institut de Planetologie et d’Astrophysique de Grenoble (IPAG)
    BP 53, 38041 Grenoble Cedex 9, France
    +33 6 8739 6285
    jean-luc.beuzit@univ-grenoble-alpes.fr

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    rhook@eso.org

    1
    One of the most challenging and exciting areas of astronomy today is the search for exoplanets — other worlds orbiting other stars. The exoplanet HIP 65426b has recently been discovered using the SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch instrument) instrument on ESO’s Very Large Telescope (VLT). Some 385 light-years from us, HIP 65426b is the first planet that SPHERE has found [1] — and it turns out to be a particularly interesting one.

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO SPHERE extreme adaptive optics system and coronagraphic facility on the extreme adaptive optics system and coronagraphic facility on the VLT, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level

    The planet is warm (between 1000 and 1400 degrees Celsius), and is between six and twelve times the mass of Jupiter. It seems to have a very dusty atmosphere filled with thick cloud, and it orbits a hot, young star that rotates surprisingly fast. Unusually, given its age, the star does not appear to be surrounded by a disc of debris, and the absence of a disc raises puzzling questions about how the planet formed in the first place. The planet may have been formed in a disc of gas and dust and when the disc rapidly dissipated, it interacted with other planets to move to a more distant orbit, where we see it now. Alternatively, the star and the planet may have formed together as a binary system in which the more massive component prevented the other would-be star from accumulating sufficient matter to actually become a star. The planet’s discovery gives astronomers the opportunity to study the composition and location of clouds in its atmosphere, and to test theories of the formation, evolution, and physics of exoplanets.

    SPHERE is a powerful planet finder installed on Unit Telescope 3 of the VLT. Its science goal is to detect and study new giant exoplanets around nearby stars using the direct imaging method [2]. This method aims to directly capture images of exoplanets and debris discs around stars, rather like taking a photograph. Direct imaging is difficult because the light of a star is so powerful that the feeble light reflected by orbiting planets is overwhelmed by the starlight. But SPHERE is cleverly designed to bypass this obstacle and to look specifically for the polarised light reflected off a planet’s surface.

    This image was captured as part of a survey programme called SHINE (SpHere INfrared survey for Exoplanets). SHINE aims to image 600 young nearby stars in the near-infrared using SPHERE’s high contrast and high angular resolution to discover and characterise new planetary systems and explore how they formed.

    Notes

    [1] A previous ESO press release reported an earlier SPHERE observation that was interpreted as a planet. However, that interpretation has been called into doubt and so HIP 65426b is currently the first reliable detection of an exoplanet by SPHERE.

    [2] When scouring the Universe for exoplanets, astronomers have numerous tools at their disposal. Many planet detection methods are indirect — astronomers can detect the tell-tale dip in a star’s brightness when a planet transits across its face, or measure the tiny wobble in a star’s motion caused by the gravitational tug of any orbiting planets.

    Planet transit. NASA/Ames

    However, there is a more direct method of finding an exoplanet: direct imaging.

    See the full article here .

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

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

    ESO VLT
    VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

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

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
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