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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

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    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).

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    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

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    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.

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    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?”

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    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” 

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    aeon

    9.19.17
    Ramin Skibba

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    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

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    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.

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    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

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    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

    Keck NASA

    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.

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    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

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    The IAC 80 telescope of the Observatorio del Teide.

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    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.

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    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.

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    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

     
  • richardmitnick 9:17 am on May 29, 2017 Permalink | Reply
    Tags: , , , , , Doppler shifts, Exoplanet research, ,   

    From AAO: “A new laser at the AAT!” 

    AAO Australian Astronomical Observatory

    Australian Astronomical Observatory

    6

    A new laser at the AAT! Last week we took delivery of the new laser frequency comb for the Veloce spectrograph (https://newt.phys.unsw.edu.au/~cgt/Veloce/Veloce.html), which will replace the AAT’s venerable UCLES instrument early next year. The laser frequency comb will provide Veloce with an ultra-stable calibration source, enabling it to separate tiny Doppler shifts in the wavelength of light from a star caused by orbiting exoplanets from slight drifts in the instrument itself. With this Veloce will be able to measure Doppler shifts of less than 1 part in 300 000 000, equivalent to measuring the motion of a star to a precision of less than 3.6 kilometres per hour!

    1

    2

    3

    4

    ^AJH

    See the full article here .

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    AAO Anglo Australian Telescope Exterior
    AAO Anglo Australian Telescope Interior
    Anglo-Australian telescope

    The Australian Astronomical Observatory, a division of the Department of Industry, Innovation and Science, operates the Anglo-Australian and UK Schmidt telescopes on behalf of the astronomical community of Australia. To this end the Observatory is part of and is funded by the Australian Government. Its function is to provide world-class observing facilities for Australian optical astronomers.

     
  • richardmitnick 12:10 pm on April 20, 2017 Permalink | Reply
    Tags: Exoplanet research, Oceans galore: new study suggests most habitable planets may lack dry land,   

    From phys.org: “Oceans galore: new study suggests most habitable planets may lack dry land” 

    physdotorg
    phys.org

    April 20, 2017
    Dr Robert Massey

    1
    Continents on other habitable worlds may struggle to break above sea level, like much of Europe in this illustration, representing Earth with an estimated 80% ocean coverage. Credit: Antartis / Depositphotos.com

    When it comes to exploring exoplanets, it may be wise to take a snorkel along. A new study, published in a paper in the journal Monthly Notices of the Royal Astronomical Society, has used a statistical model to predict that most habitable planets may be dominated by oceans spanning over 90% of their surface area.

    The author of the study, Dr Fergus Simpson of the Institute of Cosmos Sciences at the University of Barcelona, has constructed a statistical model – based on Bayesian probability – to predict the division between land and water on habitable exoplanets.

    For a planetary surface to boast extensive areas of both land and water, a delicate balance must be struck between the volume of water it retains over time, and how much space it has to store it in its oceanic basins. Both of these quantities may vary substantially across the full spectrum of water-bearing worlds, and why the Earth’s values are so well balanced is an unresolved and long-standing conundrum.

    Simpson’s model predicts that most habitable planets are dominated by oceans spanning over 90% of their surface area. This conclusion is reached because the Earth itself is very close to being a so-called ‘waterworld’ – a world where all land is immersed under a single ocean.

    “A scenario in which the Earth holds less water than most other habitable planets would be consistent with results from simulations, and could help explain why some planets have been found to be a bit less dense than we expected,” explains Simpson.

    In the new work, Simpson finds that the Earth’s finely balanced oceans may be a consequence of the anthropic principle – more often used in a cosmological context – which accounts for how our observations of the Universe are influenced by the requirement for the formation of sentient life.

    “Based on the Earth’s ocean coverage of 71%, we find substantial evidence supporting the hypothesis that anthropic selection effects are at work,” comments Simpson.

    To test the statistical model Simpson has taken feedback mechanisms into account, such as the deep water cycle, and erosion and deposition processes. He also proposes a statistical approximation to determine the diminishing habitable land area for planets with smaller oceans, as they become increasingly dominated by deserts.

    Why did we evolve on this planet and not on one of the billions of other habitable worlds? In this study Simpson suggests the answer could be linked to a selection effect involving the balance between land and water.

    “Our understanding of the development of life may be far from complete, but it is not so dire that we must adhere to the conventional approximation that all habitable planets have an equal chance of hosting intelligent life,” Simpson concludes.

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 11:46 am on March 1, 2017 Permalink | Reply
    Tags: , , , , , Exoplanet research, Volcanic hydrogen spurs chances of finding exoplanet life   

    From Cornell: “Volcanic hydrogen spurs chances of finding exoplanet life” 

    Cornell Bloc

    Cornell University

    February 27, 2017
    Blaine Freidlander

    1
    (Photo : Wikimedia Commons/E. Klett, U.S. Fish and Wildlife Service)

    2

    Hunting for habitable exoplanets now may be easier: Cornell astronomers report that hydrogen pouring from volcanic sources on planets throughout the universe could improve the chances of locating life in the cosmos.

    Planets located great distances from stars freeze over. “On frozen planets, any potential life would be buried under layers of ice, which would make it really hard to spot with telescopes,” said lead author Ramses Ramirez, research associate at Cornell’s Carl Sagan Institute. “But if the surface is warm enough – thanks to volcanic hydrogen and atmospheric warming – you could have life on the surface, generating a slew of detectable signatures.”

    Combining the greenhouse warming effect from hydrogen, water and carbon dioxide on planets sprinkled throughout the cosmos, distant stars could expand their habitable zones by 30 to 60 percent, according to this new research. “Where we thought you would only find icy wastelands, planets can be nice and warm – as long as volcanoes are in view,” said Lisa Kaltenegger, Cornell professor of astronomy and director of the Carl Sagan Institute.

    3
    Ramses Ramirez, research associate at Cornell’s Carl Sagan Institute, left, and Lisa Kaltenegger, professor of astronomy and director of the Sagan Institute.

    Their research, “A Volcanic Hydrogen Habitable Zone,” is published today in The Astrophysical Journal Letters.

    The idea that hydrogen can warm a planet is not new, but an Earth-like planet cannot hold onto its hydrogen for more than a few million years. Volcanoes change the concept.

    “You get a nice big warming effect from volcanic hydrogen, which is sustainable as long as the volcanoes are intense enough,” said Ramirez, who suggested the possibility that these planets may sustain detectable life on their surface.

    A very light gas, hydrogen also “puffs up” planetary atmospheres, which will likely help scientists detect signs of life. “Adding hydrogen to the air of an exoplanet is a good thing if you’re an astronomer trying to observe potential life from a telescope or a space mission. It increases your signal, making it easier to spot the makeup of the atmosphere as compared to planets without hydrogen,” said Ramirez.

    In our solar system, the habitable zone extends to 1.67 times the Earth-sun distance, just beyond the orbit of Mars. With volcanically sourced hydrogen on planets, this could extend the solar system’s habitable zone reach to 2.4 times the Earth-sun distance – about where the asteroid belt is located between Mars and Jupiter. This research places a lot of planets that scientists previously thought to be too cold to support detectable life back into play.

    “We just increased the width of the habitable zone by about half, adding a lot more planets to our ‘search here’ target list,” said Ramirez.

    3
    Stellar temperature versus distance from the star compared to Earth for the classic habitable zone (shaded blue) and the volcanic habitable zone extension (shaded red). Credit: Ramses Ramirez

    Atmospheric biosignatures, such as methane in combination with ozone – indicating life – will likely be detected by the forthcoming, next-generation James Webb Space Telescope, launching in 2018, or the approaching European Extremely Large Telescope, first light in 2024.

    NASA reported Feb. 22 finding seven Earth-like planets around the star Trappist-1. “Finding multiple planets in the habitable zone of their host star is a great discovery because it means that there can be even more potentially habitable planets per star than we thought,” said Kaltenegger. “Finding more rocky planets in the habitable zone – per star – increases our odds of finding life.”

    With this latest research, Ramirez and Kaltenegger have possibly added to that number by showing that habitats can be found, even those once thought too cold, as long as volcanoes spew enough hydrogen. Such a volcanic hydrogen habitable zone might just make the Trappist-1 system contain four habitable zone planets, instead of three. “Although uncertainties with the orbit of the outermost Trappist-1 planet ‘h’ means that we’ll have to wait and see on that one,” said Kaltenegger.

    The Simons Foundation and the Cornell Center for Astrophysics and Planetary Science funded this research.

    See the full article here .

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    Once called “the first American university” by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.

    Today’s Cornell reflects this heritage of egalitarian excellence. It is home to the nation’s first colleges devoted to hotel administration, industrial and labor relations, and veterinary medicine. Both a private university and the land-grant institution of New York State, Cornell University is the most educationally diverse member of the Ivy League.

    On the Ithaca campus alone nearly 20,000 students representing every state and 120 countries choose from among 4,000 courses in 11 undergraduate, graduate, and professional schools. Many undergraduates participate in a wide range of interdisciplinary programs, play meaningful roles in original research, and study in Cornell programs in Washington, New York City, and the world over.

     
  • richardmitnick 10:28 pm on February 13, 2017 Permalink | Reply
    Tags: , , , , Exoplanet research,   

    From Keck: “Over 100 New Exoplanet Candidates Discovered With W. M. Keck Observatory” 

    Keck Observatory

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

    Keck Observatory

    February 13, 2017
    Andrea Lum
    Bennet Group Strategic Communications
    808-286-9569
    andrea@bennetgroup.com

    Rich Matsuda
    W. M. Keck Observatory
    (808) 881-3822
    communications@keck.hawaii.edu

    1
    HIRES instrument helps detect potential exoplanets. Artist’s conceptions of the probable planet orbiting a star called GJ 411, courtesy of Ricardo Ramirez.

    Keck HIRES
    Keck HIRES

    International team of astronomers releases the largest-ever compilation of exoplanet-detecting observations, made from observatory atop Maunakea

    An international team of astronomers today released a compilation of almost 61,000 individual measurements made on more than 1,600 stars, used to detect exoplanets elsewhere in our Milky Way galaxy. The compilation includes data on over 100 new potential exoplanets. The entire dataset was observed using one of the twin telescopes of the W. M. Keck Observatory on Maunakea over the past two decades. The search for new worlds elsewhere in our Milky Way galaxy is one of the most exciting frontiers in astronomy today. The paper is published in the Astronomical Journal.

    HIRES instrument helps detect potential exoplanets

    “The work of this team and their willingness to share data and techniques unveils a world of new possibilities, vastly increasing the ability of astronomers everywhere to perform in-depth studies of these exoplanet systems,” said Hilton Lewis, Keck Observatory Director. “Our observatory is proud to be the source of these discoveries, thanks to our cutting-edge instrumentation and the unparalleled observing conditions atop Maunakea.”

    The astronomers used a highly specialized instrument called the High Resolution Echelle Spectrometer, or HIRES, mounted on the 10-meter Keck-I telescope. The instrument detects tiny wobbles of nearby stars caused by the gravitational pull of planets orbiting those stars -a sensitive and challenging phenomenon to measure. Powerful instrumentation and sophisticated algorithms are needed to extract the signature of the exoplanets.

    “HIRES is an incredible tool, part of the suite of sensitive instruments used to perform all kinds of extraordinary observations with our twin telescopes,” said Greg Doppmann, Keck Observatory Support Astronomer. “Our scientific and technical support team brings their A-game daily-a precise focus on even the tiniest details-to ensure that these instruments are ready to deploy for each night of observing.”

    Contributors to the international team include representatives from the Carnegie Institution for Science, University of California at Santa Cruz, Yale University, University of Hertfordshire, and Universidad de Chile.

    KCWI arrived by ship from Los Angeles on January 20 and was carefully transported up to the observatory atop Maunakea. The instrument will be installed and tested, followed by the first observations in the coming months.

    For more background information, please visit:

    https://carnegiescience.edu/node/2141

    http://news.ucsc.edu/2017/02/hires-data-release.html

    http://news.mit.edu/2017/dataset-nearby-stars-available-public-exoplanets-0213

    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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