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  • 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
    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    (808) 554-0567

    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.


    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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    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.
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  • 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


    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

    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.

    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

    The IAC 80 telescope of the Observatorio del Teide.

    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.

    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.

    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: , , , , ESO SPHERE on the VLT, 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

    Jean-Luc Beuzit
    Institut de Planetologie et d’Astrophysique de Grenoble (IPAG)
    BP 53, 38041 Grenoble Cedex 9, France
    +33 6 8739 6285

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

    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.


    [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

    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 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 to be built at Cerro Armazones at 3,060 m

    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, , Veloce spectrograph   

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

    AAO Australian Astronomical Observatory

    Australian Astronomical Observatory


    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!






    See the full article here .

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    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” 


    April 20, 2017
    Dr Robert Massey

    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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    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

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


    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.

    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.

    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

    Rich Matsuda
    W. M. Keck Observatory
    (808) 881-3822

    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:




    See the full article here .

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    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 4:32 pm on February 2, 2017 Permalink | Reply
    Tags: , , , , , Exoplanet research, High Energy Density Science instrument at the European XFEL or HED   

    From XFEL: “DFG funds investigation of exoplanets at European XFEL” 

    XFEL bloc

    European XFEL

    02 February 2017
    No writer credit found

    Interdisciplinary research project funded with 2 M€

    With the help of telescopes on Earth and in space, several thousand planets outside of our solar system have been discovered since 1996. Observation data such as mass, radius, and distance from their central star give only a few details about the composition and origin of these exoplanets. The research unit “Matter Under Planetary Interior Conditions”, led by the University of Rostock and including scientists from European XFEL will find out more about these planets in the framework of a grant funded by the German Research Foundation (DFG). The researchers want to draw inferences about exoplanets based on the planets in our own solar system and develop suitable methods for this purpose. Their interdisciplinary collaboration comprises theory, planetary modelling, and experiments. This comprises experimental investigations of materials under extreme conditions, such as those found inside of planets at, among others, the European XFEL and the research centre DESY. The DFG will fund the project for the next three years with a total contribution of around 2 million euro.

    “A strength of our proposal is that it combines theory, planetary modelling, and experiments in order to learn more about the composition and development of planets inside and outside of our solar system”, says Prof. Ronald Redmer of the University of Rostock, spokesperson for the research unit. In addition, the findings will be used for the evaluation of observation data from satellite missions.

    This artist concept depicts in the foreground planet Kepler-62f, a super-Earth-size planet in the habitable zone of its star, which is seen peeking out from behind the right edge of the planet.

    The Kepler Space Telescope has discovered a large number of planets between one and twenty times the mass of the Earth in orbits close to Sun-like stars.

    NASA/Kepler Telescope
    NASA/Kepler Telescope

    These exoplanets are defined as so-called “super-Earths”, which have a similar density and masses up to ten times that of the Earth, and neptunian planets, which have a similar density as the planet Neptune in our solar system. Neptune has a solid core; a mantle composed of liquid water, ammonia, and methane; as well as an atmosphere made of hydrogen, helium, and methane. In the interiors of all of these types of planets pressures can be many times higher than those inside the Earth and temperatures can reach several thousand degrees Celsius. The researchers want to find out how the principal constituents of these planets—for example, magnesium oxide and silicates for super-Earths as well as water, methane, and ammonia for neptunian planets—behave under these conditions.

    The High Energy Density Science instrument at the European XFEL, or HED for short, enables experimental investigations of extreme states of matter like those found inside of planets.


    “In the course of these experiments, we can generate brief spikes in pressure up to a million bar on the sample”, explains Karen Appel, a scientist at HED and project leader for this part of the research unit’s proposal. “The pressure would be as strong as having the weight of the world’s tallest building, the Burj Khalifa in Dubai, on someone’s fingertip.” The high pressures and temperatures at the HED instrument are generated through a shockwave triggered by an intense laser pulse. If the material decompresses after the shock, it goes through many different combinations of pressures and temperatures with distinctive material characteristics within very small fractions of a second. The short light flashes of the European XFEL enable sharp snapshots of these states and their properties to be taken. “Through X-ray scattering and X-ray spectroscopy, we will be able to determine the time-resolved structure and properties of magnesium oxide and silicates under these conditions”, says Appel. “With that, we can gather essential data for planetary modelling.”

    Other than the Universities of Rostock and Bayreuth and European XFEL, DESY and the DLR Institute for Planetary Research in Berlin are also participating.

    See the full article here .

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    XFEL Campus

    The Hamburg area will soon boast a research facility of superlatives: The European XFEL will generate ultrashort X-ray flashes—27 000 times per second and with a brilliance that is a billion times higher than that of the best conventional X-ray radiation sources.

    The outstanding characteristics of the facility are unique worldwide. Starting in 2017, it will open up completely new research opportunities for scientists and industrial users.

  • richardmitnick 10:43 am on February 2, 2017 Permalink | Reply
    Tags: , , Atmospheres can protect and nurture or they can destroy, “L” is for the longevity of a potentially civilized intelligent world, , , , Exoplanet research, , , , The fate of Earth is indeed in our hands   

    From Many Worlds: “Do Intelligent Civilizations Across the Galaxies Self Destruct? For Better and Worse, We’re The Test Case” 

    NASA NExSS bloc


    Many Words icon

    Many Worlds

    Marc Kaufman

    The Eastern Seaboard as seen from the International Space Station in 2012. (NASA)

    In 1950, while working at Los Alamos National Laboratory, renowned physicist Enrico Fermi was lunching with colleagues including Edward Teller, Herbert York an Emil Konopinski. The group talked and laughed about a spate of recent UFO reports during the meal, as well as a cartoon about who might be stealing garbage can top.

    A bit later in the meal Fermi famously asked more seriously, “Where are they?” Sure, there were many bogus reports back then about alien flying saucers, but Fermi was asking what has turned out to be a significant and long-lasting question.

    If there are billions of exoplanets out there — as speculated back then but proven now — why have there been no bona fide reports of advanced extraterrestrials visiting Earth, or somehow leaving behind their handiwork?

    Many answers have been offered in the following decades — that we are alone in the universe, that the distances between solar systems are too great to travel, that Earth became home to life early in the galaxy’s history and other planets are only now catching up, that life might be common in the universe but intelligent life is not.

    I would like to focus on another response, however, one that came to mind often while reading a new book by the former holder of the astrobiology chair at the Library of Congress, planetary scientist David Grinspoon.

    This potential explanation is among the most unsettling: that intelligent and technologically advanced beings are likely to ultimately destroy themselves. Along with the creativity, the prowess and the gumption, intelligence brings with it an inherent instinct for unsustainable expansion and unintentional self destruction.

    I should say right off that this is not a view shared by Grinspoon. His Earth in Human Hands, in fact, argues with data and conviction that humans are more likely than not to ultimately find ways to work together and avoid looming global threats from climate change, incoming asteroids, depleting the ozone layer and myriad other potential sources of mass extinction.

    But his larger point is the sobering one: that the fate of Earth is, indeed, in our hands. We humans are a force shaping the planet that is as powerful as a ring of volcanoes, a giant impactor from space, the long-ago rise of lifeforms that could, and did, dramatically change our atmosphere and along the way caused near global extinction.

    It may sound odd, but as he sees it we are now the planet’s most powerful and consequential force of nature.

    Since the Industrial Revolution and the spread of technology over the past 200 years, humans have become the dominant force on the planet, says David Grinspoon, the first Chair in Astrobiology at the Library of Congress. (Credit: Tony Steele)

    “What I’ve sought to do is describe what is reality on our planet,” Grinspoon told me. “Some people have been hostile and told me it’s arrogant to say humans have so much control over the fate of the planet, and I agree that it’s a sobering thing.”

    But the Earth has been and will be dramatically changed by us. The big question for the future is whether change can be for the better, or will it be unsustainable and for the worse.”

    While Grinspoon’s major themes involve competing paths for the future of our planet, they consistently are based on and informed by knowledge gained in recent decades about planets in our solar system and those very far away. The logic and track record of the search for intelligent life beyond Earth (SETI) also plays a role, as does the author’s relationships — initially via family in childhood — with Carl Sagan and some of the scientists he mentored.

    For instance, Grinspoon has studied Venus and the evolution of its atmosphere. He says that an understanding of the runaway greenhouse effect that created surface temperatures of 800 degrees F has been instumental in the study of climate change on Earth.

    David Grinspoon is a senior scientist at the Planetary Science Institute, and the author of “Earth in Human Hands.”

    Similarly, the disappearance of much of the Martian atmosphere left the once warmer planet frigid and likely lifeless. Sagan’s work on the dust storms of Mars, which have the effect of making the planet colder still, was an early scientific foray into understanding the importance of atmosphere and climate on a potential biosphere. So was Sagan’s work on the possible effects of atomic war — the globally life-destroying “nuclear winter.”

    The clear inference: Planetary atmospheres can change, as ours is doing now with major buildups in carbon dioxide. Atmospheres can protect and nurture, or they can destroy.

    And Exhibit A is the three rocky solar system planets in what is a slightly expanded habitable zone. But only one supports life.

    The buildup of carbon dioxide in the atmosphere and oceans since the onset of the industrial revolution, Grinspoon writes, is a prime example of how intelligent people and their technology can unintentionally have a huge impact on nature and the planet. The jury remains out as to how humanity will respond.

    But Grinspoon also points to the way that nations around the globe responded to the discovery that the ozone layer was being depleted as an example of how humanity can repair unintentional yet potentially extinction-threatening challenges.

    It took a while, but the artificial refrigerants — chlorofluorocarbons (CFCs) — causing the damage were ultimately curtailed and then banned, and there are signs that the worrisome holes in the ozone layer are if not shrinking, at least no longer growing.

    The Drake equation, created by astronomer Frank Drake in 1961, assesses the probability of how many planets in our galaxy might have civilizations that can communicate. The last factor — the “L” for longevity — is considered key. Drake was one of the founders of SETI, and its effort to detect signals from intelligent life beyond Earth.

    This brings us back to the Fermi paradox, and the apparent absence of signs of extraterrestrial intelligence.

    Fermi, and many others, have assumed that successful, technological civilizations elsewhere would have the desire and ultimately know-how to expand beyond their original planet and colonize others. Indeed, early SETI gatherings here and in the former Soviet Union took that drive to expand for granted, a reflection of attitudes of the times.

    This presumed drive to colonize was often discussed as either a kind of biological imperative or an acknowledgement that these “intelligent” civilizations are likely to have seriously damaged their own planets through unsustainable and hazardous growth. Either way, they would be on the move.

    Yet after more than a half century of listening for signals from these presumed intelligent and mobile beings, the SETI effort to detect such life via radio telescopes has come up empty. There are many potential reasons why, but let’s focus on the one introduced earlier.

    The pioneering Drake equation, first put forward in 1961, attempts to assess the probability of finding intelligent civilizations beyond Earth based on factors such as rate of star formation in the galaxy, the number of planets formed and then the percentage with life, then the number with complex life and finally intelligent and technologically-sophisticated life. But it’s the “L” at the end of the equations, says Grinspoon, that is widely considered the most important.

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

    The “L” is for the longevity of a potentially civilized, intelligent world, or “the length of time over which such civilizations release detectable signals.”

    Of all the components of the Drake equation, which is filled with unknowns and partially known estimates, L is no doubt the least well defined. After all, no extraterrestrial life, and certainly no intelligent life, has ever be detected.

    Yet as describe by Grinspoon, “L” — which for Earth is about 200 years now — is the key.

    “Let’s say that it’s impossible for a civilization with very powerful technology to last for 10,000 years, or even 1,000 years. That makes the likelihood of ever making contact with them vanishingly small even if life and intelligence are out there. The chances of them being close enough to detect and communicate with are pretty much nil.”

    If the opposite is true, if it’s possible for a civilization to get over their technological adolescence, then they ought to be detectable. Actually, they could last for millions of years using their technology to enhance and protect the planet.”

    Planets face all kinds of dire threats, and catastrophes and extinctions are the rule. But if technology can be used intentionally for the benefit the planet — like protecting it from an asteroid or avoiding the next Ice Age – longevity would clearly improve greatly.”

    This interstellar view, he says, helps to see more clearly what is happening on Earth. Now that through our technologies we have become the prime movers regarding the planet’s health and safety, it is really up to us as a species to choose between allowing these “advances” to knowingly or unintentionally harm the planet, or to consciously use technology to make it better.

    Grinspoon does not see our current century as one when the effects of technology are likely to be intentionally positive. But he does see the movement towards a more sustainable planet to be irreversible, whatever blips might come our way. What’s more, he said, fossil fuels will be largely gone by 2100 and there’s reason to believe the world’s human population will have stabilized — two enormous changes that favor a longer-lived human civilization.

    “The long-held view that humans will always expand, that they will maintain that biologically primitive imperative, that growth is always good — it’s interesting to wonder if those assumptions aren’t inherently wrong,” he said.

    “I suggest that true ‘intelligence’ able to sustain itself involves an inherent questioning of those values, and that a more measured and strategic growth pattern, or even material stasis might be values that come with a more universal intelligence.”

    Whether that intelligence is on Earth or many hundreds of light years away.

    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 1:38 pm on January 20, 2017 Permalink | Reply
    Tags: , , , , , Exoplanet research, HATnet,   

    From AAS NOVA: “Reinflating Giant Planets” 


    American Astronomical Society

    18 January 2017
    Susanna Kohler

    Artist’s impression of a hot Jupiter exoplanet transiting across the face of its host star. [NASA/ESA/C. Carreau]

    Two new, large gas-giant exoplanets have been discovered orbiting close to their host stars. A recent study examining these planets — and others like them — may help us to better understand what happens to close-in hot Jupiters as their host stars reach the end of their main-sequence lives.

    Unbinned transit light curves for HAT-P-65b. [Adapted from Hartman et al. 2016]

    Oversized Giants

    The discovery of HAT-P-65b and HAT-P-66b, two new transiting hot Jupiters, is intriguing. These planets have periods of just under 3 days and masses of roughly 0.5 and 0.8 times that of Jupiter, but their sizes are what’s really interesting: they have inflated radii of 1.89 and 1.59 times that of Jupiter.

    These two planets, discovered using the Hungarian-made Automated Telescope Network (HATNet) in Arizona and Hawaii, mark the latest in an ever-growing sample of gas-giant exoplanets with radii larger than expected based on theoretical planetary structure models.

    HATNet telescopes at Fred Lawrence Whipple Observatory, Mount Hopkins, Arizona. Photo credit: Gaspar Bakos.pple-observatory-mount-hopkins-arizona-photo-credit-gaspar-bakos
    HATNet telescopes at Fred Lawrence Whipple Observatory, Mount Hopkins, Arizona. Photo credit: Gaspar Bakos

    HATnet, Mauna Kea Hawaii USA
    HATNet, Mauna Kea Hawaii USA

    What causes this discrepancy? Did the planets just fail to contract to the expected size when they were initially formed, or were they reinflated later in their lifetimes? If the latter, how? These are questions that scientists are only now starting to be able to address using statistics of the sample of close-in, transiting planets.

    Exploring Other Planets

    Unbinned transit light curves for HAT-P-66b. [Hartman et al. 2016]

    Led by Joel Hartman (Princeton University), the team that discovered HAT-P-65b and HAT-P-66b has examined these planets’ observed parameters and those of dozens of other known close-in, transiting exoplanets discovered with a variety of transiting exoplanet missions: HAT, WASP, Kepler, TrES, and KELT. Hartman and collaborators used this sample to draw conclusions about what causes some of these planets to have such large radii.

    The team found that there is a statistically significant correlation between the radii of close-in giant planets and the fractional ages of their host stars (i.e., the star’s age divided by its full expected lifetime). The two newly discovered hot Jupiters with inflated radii, for instance, are orbiting stars that are roughly 84% and 83% through their life spans and are approaching the main-sequence turnoff point.

    Fractional age of the host stars of close-in transiting exoplanets vs. the planet’s radius. There is a statistically significant correlation between age and planet radius. [Adapted from Hartman et al. 2016]

    Late-Life Reinflation

    Hartman and collaborators propose that the data support the following scenario: as host stars evolve and become more luminous toward the ends of their main-sequence lifetimes, they deposit more energy deep into the interiors of the planets closely orbiting them. These close-in planets then increase their equilibrium temperatures — and their radii reinflate as a result.

    Based on these results, we would expect to continue to find hot Jupiters with inflated radii primarily orbiting closely around older stars. Conversely, close-in giant planets around younger stars should primarily have non-inflated radii. As we continue to build our observational sample of transiting hot Jupiters in the future, we will be able to see how this model holds up.


    J. D. Hartman et al 2016 AJ 152 182. doi:10.3847/0004-6256/152/6/182

    See the full article here .

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