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  • richardmitnick 11:23 am on October 1, 2019 Permalink | Reply
    Tags: "Astronomers Detect a 'Hot Jupiter' With a Staggering 18-Hour-Short Orbit", , , , , , Hot Jupiters, NGTS-10b,   

    From Science Alert: “Astronomers Detect a ‘Hot Jupiter’ With a Staggering 18-Hour-Short Orbit” 


    From Science Alert

    1 OCT 2019

    We have a new record. Perhaps 1,060 light-years away, a gas giant called NGTS-10b is whipping around its star so closely, it completes an entire orbit in just 18.4 hours.

    Artist’s impression of a transiting gas giant. (NASA, ESA and G. Bacon)

    That’s nearly as close as the planet can get to the host star without being ripped apart by gravitational forces. But it will get closer.

    Astronomers have estimated that the exoplanet is spiralling in towards the star, and will cross that ripping-apart point – called the Roche limit – in just 38 million years. It’s utterly doomed.

    The finding makes this solar system an incredible laboratory for studying tidal interactions between a star and a perilously close giant exoplanet. A paper describing the exoplanet – which belongs to the ‘hot Jupiter’ type – has been published on pre-print resource arXiv [submitted to MNRAS].

    Hot Jupiters are fascinating exoplanets. As the name suggests, they are gas giants like Jupiter; unlike Jupiter, however, they orbit very closely to their host stars, with orbital periods of less than 10 days. This is what makes them “hot” (and here you were thinking it was the swimsuits).

    According to current models of planet formation, technically hot Jupiters shouldn’t exist. A gas giant can’t form that close to their star, because the gravity, radiation, and intense stellar winds ought to keep the gas from clumping together.

    However, they do exist; of the over 4,000 confirmed exoplanets discovered to date, up to 337 could be hot Jupiters. It’s thought that they form farther out in their planetary systems, then migrate inwards towards the star.

    We may not know much about their mysterious births, but hot Jupiters that are particularly close to their stars can tell us a lot about star-planet tidal interactions. Hence, they are among the most studied exoplanets in the galaxy.

    Until this latest breakneck discovery, only six of these enigmatic gas giants had ever been detected with an orbital period of less than one day – WASP-18b (22.6 hours), WASP-19b (18.9 hours), WASP-43b (19.5 hours), WASP-103b (22.2 hours), HATS-18b (20.1 hours) and KELT-16b (23.3 hours).

    NGTS-10b, discovered using the ground-based Next-Generation Transit Survey in Paranal, Chile, marks the seventh of these ultra-close hot Jupiters, and it has the shortest orbital period of them all.

    ESO NGTS an array of twelve 20-centimetre telescopes at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    Between 21 September 2015 and 14 May 2016, a single telescope observed the star now known as NGTS-10 over 237 nights. The survey wasn’t officially operational yet, but it captured 220,918 10-second exposures of the star during this commissioning phase.

    It seemed like a relatively unremarkable main sequence star – around 10 billion years old K-type orange star, just under 70 percent of the Sun’s size and mass.

    But a closer look at those images revealed that the star was dimming slightly every 18.4 hours. So an international team of astronomers led by James McCormac of the University of Warwick set to work, using that data and additional observations to characterise the exoplanet responsible for the dimming.

    They determined that NGTS-10b is just over 1.2 times the size of Jupiter, and just over 2.1 times its mass. And it’s orbiting the star at 1.46 times the Roche radius – meaning it’s right on the verge (in cosmic time) of tidal devastation.

    At such proximity to the star, even though it’s not yet close enough to pull NGTS-10b apart, the exoplanet will be flattened at the poles as the star’s gravity pulls it out of shape, an oblate spheroid rather than a nice, plump round sphere.

    The team was careful to rule out a binary companion of the host star as a cause of the dimming. So, we are as sure as we can be that the exoplanet exists. The problem is that the light from the neighbouring stars has made it somewhat difficult to calculate an accurate distance to NGTS-10.

    The 1,060 light-year distance was calculated based on Gaia data, the most accurate three-dimensional map of the Milky Way galaxy to date, but there’s still a margin for error. If the distance is incorrect, that may mean some of the size and mass data is slightly incorrect, too.

    That issue can be resolved by studying the next release of Gaia data, due to drop in batches in 2020 and 2021.

    Meanwhile, continued observations of the system could reveal the exoplanet’s orbital decay. The team predicts that the orbit will shorten by 7 seconds over the next 10 years. If astronomers can obtain precise enough measurements of the system, they may be able to see it happening.

    See the full article here .


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  • richardmitnick 10:06 am on September 19, 2019 Permalink | Reply
    Tags: "These Weird Exoplanets Could Have Clouds Made of Rock", , , , , , Hot Jupiters,   

    From Curiosity and McGill University: “These Weird Exoplanets Could Have Clouds Made of Rock” 

    McGill University

    From McGill University

    Curiosity Makes You Smarter

    From Curiosity

    The dark side of extrasolar planets share surprisingly similar temperatures.

    September 17, 2019

    Cynthia Lee
    McGill Media Relations Office

    A new study by McGill University astronomers has found that the temperature on the nightsides of different hot Jupiters is surprisingly uniform, suggesting the dark side of these massive gaseous planets have clouds made of minerals and rocks.

    Using data from the Spitzer Space and the Hubble Space telescopes, the researchers from the McGill Space Institute found that the nightside temperature of 12 hot Jupiters they studied was about 800°C.

    Graphic: Schematic of clouds on the night side of a hot Jupiter exoplanet. The underlying atmosphere is over 800 C, hot enough to vaporize rocks. Atmospheric motion from the deep atmosphere or from the hotter dayside bring the rock vapour to cooler regions, where it condenses into clouds, and possibly rains down into the atmosphere below. These clouds of condensed rock block outgoing thermal radiation, making the planet’s nightside appear relatively cool from space.

    NASA/Spitzer Infrared Telescope

    NASA/ESA Hubble Telescope

    Unlike our familiar planet Jupiter, so-called hot Jupiters circle very close to their host star — so close that it typically takes fewer than three days to complete an orbit.  As a result, hot Jupiters have daysides that permanently face their host stars and nightsides that always face the darkness of space, similarly to how the same side of the Moon always faces the Earth. The tight orbit also means these planets receive more sunlight from their star, which is what makes them extremely hot on the dayside. But scientists had previously measured significant amounts of heat on the nightside of hot Jupiters, as well, suggesting some kind of energy transfer from one side to the other.

    “Atmospheric circulation models predicted that nightside temperatures should vary much more than they do,” said Dylan Keating, a Physics PhD student under the supervision of McGill professor Nicolas Cowan. “This is really surprising because the planets we studied all receive different amounts of irradiation from their host stars and the dayside temperatures among them varies by almost 1700°C.”

    Keating, the first author of a new Nature Astronomy study describing the findings, said the nightside temperatures are probably the result of condensation of vaporized rock in these very hot atmospheres.

    “The uniformity of the nightside temperatures suggests that clouds on this side of the planets are likely very similar to one another in composition. Our data suggest that these clouds are likely made of minerals such as manganese sulfide or silicates, or rocks,” Keating explained.

    According to Cowan, because the basic physics of cloud formation are universal, the study of the nightside clouds on hot Jupiters could give insight into cloud formation elsewhere in the Universe, including on Earth. Keating said that future space telescope missions – such as the James Webb Space Telescope and the European Space Agency’s ARIEL mission – could be used to further characterize the dominant cloud composition on hot Jupiter nightsides, as well as to improve models of atmospheric circulation and cloud formation of these planets. 

    “Observing hot Jupiters at both shorter and longer wavelengths will help us determine what types of clouds are on the nightsides of these planets,” Keating explained.

    See the full article here .


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  • richardmitnick 3:01 pm on March 16, 2018 Permalink | Reply
    Tags: , , , , Hoptunes [Hot+Neptune] Egad!!, Hot Jupiters, KIAA PKG, KIAA PKU   

    From The Kavli Institute for Astronomy and Astrophysics at Peking University: “Introducing “Hoptunes”, a New Class of Exoplanets that Could Help Solve the Mystery of Worlds in Scorching Orbits” 

    The Kavli Institute for Astronomy and Astrophysics at Peking University

    March 15, 2018

    In this exoplanetary collage, the left side is an artist’s depiction of a hot Jupiter exoplanet in a tight orbit around its host sun. The right side depicts a newly described population of exoplanets, dubbed Hoptunes. These worlds range in size from a bit smaller to a bit larger than Neptune. Like their bigger Jovian cousins, Hoptunes also encircle their stars in close, scorching orbits. The background displays some of the diversity of solar systems.(Credit: Composite image by Jin Ma at the Beijing Planetarium, using public domain and Creative Commons-licensed images with credits belonging to NASA/ESA/ESO; Danielle Futselaar and Franck Marchis, SETI Institute; NASA/JPL-Caltech; NASA’s Goddard Space Flight Center; and NASA/SDO)

    Among the most baffling worlds discovered so far in the universe are “hot Jupiters.” These gas giants orbit their host stars far closer than the innermost planet in our Solar System, Mercury, orbits the Sun. Many astronomers think hot Jupiters could not have formed in such searing, star-kissed conditions, suggesting the planets somehow moved in toward their suns after initially taking shape.

    Now a new study [PNAS] offers fresh insight into the planets’ perplexing provenance, thanks to a newly described clutch of toasty worlds—dubbed Hoptunes—that are like hot Jupiters’ smaller cousins. Led by Subo Dong of the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University and Ji-Wei Xie of Nanjing University, the study finds striking similarities between the two planetary types. Akin to their bigger brethren, Hoptunes often orbit stars with higher abundances of what astronomers call metals—elements heavier than helium. Hoptunes also tend to be loner worlds, again like hot Jupiters, hogging host stars all to themselves in single-planet solar systems.

    Evidently, the processes that bring about Hoptunes likely extend to the rise of hot, giant planets, too, pointing to a shared, ultimately knowable origin.

    “Understanding how hot Jupiters form has been a detective story for decades, and the discovery of Hoptunes adds important new clues to this ongoing investigation,” said Dong, the Youth Qianren Research Professor of astronomy at KIAA. “Our study shows Hoptunes probably develop in similar conditions as hot Jupiters, which means we’re zeroing in how those conditions permit scorching planets.”

    Dong coined the name “Hoptunes” for worlds that possess anywhere from two to six times the diameter of Earth. This size range goes a bit below and above the diameter of the planet Neptune, which has a diameter of four Earths—far less than the 9.5 and 11 Earths, respectively, needed to equal Saturn’s and Jupiter’s tremendous girths. The masses for Hoptunes remain unknown, however, so astronomers do not know which of them are rocky, like Earth, or mostly gaseous, like Neptune. Thus, Dong opted against broadly calling this planetary class “hot Neptunes,” because some of them are likely more terrestrial than Neptunian in character.

    The research team first got onto the trail of Hoptunes with Kepler, NASA’s exoplanet hunting spacecraft. Kepler detects exoplanets through the slight dimming in starlight they cause when crossing the faces of their host stars.

    The team dug deeper into a large set of close-in planets initially spotted by Kepler. In order to accurately measure the planets’ sizes and the metal levels in their stars, the scientists turned to the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), located in northern China. Also known as the Guo Shoujing Telescope, it uses a technique called spectroscopy to break apart the light from stars, revealing their chemical makeup.

    LAMOST telescope located in Xinglong Station, Hebei Province, China

    Spectroscopy also indicates the strength of gravity at the surfaces of stars which, when cross-referenced with their color-coded temperature—hot stars shine blue, cool stars glow red—discloses their sizes. LAMOST can uniquely perform spectroscopy on thousands of stars simultaneously, providing astronomers with huge amounts of critical data.

    “LAMOST is currently the world’s most efficient machine in mass-producing stellar spectroscopy,” said Dong. “Using LAMOST, we were able to identify and characterize the solar systems and the host stars that harbor Hoptunes.”

    The similarities discovered between Hoptune- and hot Jupiter-hosting solar systems might support astronomers’ working theories for how colossal worlds can form. Take the observed levels of metals, or metallicity, for instance. Some astronomers think higher metallicity means greater amounts of solid material available to form planets in the gassy, dusty disks surrounding young stars. Bit by bit, the materials in the disks glom together, growing into ever larger, rocky bodies. Particularly massive bodies with powerful gravitational pulls can capture deep atmospheres of gases, forming Jupiter-like worlds or, on the smaller side, Neptunes or Uranuses. Systems with low metallicities, however, struggle to generate big planets.

    It is generally believed that giant planets need massive, solid cores to build up before they can accrete a large amount of gas. In close quarters to stars, not enough solid materials may be available to build up such suitably bulky cores. Therefore, hot Jupiters and gassy Hoptunes must somehow migrate toward their stars after initially forming. Yet the role that metal levels actually play in this migration remains unclear. One possibility is that disks with high metallicity could give birth to a large number of big planets, fostering violent gravitational interactions. This process might encourage some planets to migrate inward.

    Finally, the migration process may also have something to do with why Hoptunes and hot Jupiters are usually the only planets in their respective solar systems. The inward movement of a large world can gravitationally kick out other planets, leaving behind just a single, bullying scorcher. Notably, the team also found that Hoptunes are somewhat less “lonely” than hot Jupiters, probably because their smaller sizes make them generally less capable of expelling their fellow planets.

    To further unravel the origins of planets in tight orbits around their stars, Dong and colleagues are looking forward to soon having boatloads of new specimen worlds to study. The Transiting Exoplanet Survey Telescope (TESS), a spacecraft launching in March 2018 and led by the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology, should discover thousands of exoplanets around the closest, brightest stars.


    Many of the planets will be in tight orbits and, being nearby, quite amenable to detailed study.

    “With TESS and other upcoming missions, we expect to find a lot more hot Jupiters and Hoptunes to study,” said Dong. “I am especially looking forward to high-resolution spectroscopic studies of Hoptunes that could yield their masses, which could provide important evidence to crack the case of these roaster planets.”

    Other members of the research team and paper co-authors are Ji-Lin Zhou of Nanjing University, Zheng Zheng of the University of Utah, and Ali Luo of the National Astronomical Observatories of the Chinese Academy of Sciences. The research is funded, in part, by the National Natural Science Foundation of China, the Chinese Academy of Sciences, the Key Development Program of Basic Research of China, and the Foundation for the Author of National Excellent Doctoral Dissertation of People’s Republic of China.

    See the full article here .

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    KIAA PKU one of many assemblages

    The Kavli Institute for Astronomy and Astrophysics (KIAA), at Peking University in Beijing, is both a tribute to China’s rich scientific tradition and an extension of it.

    Established in 2006 and becoming operational in 2007, KIAA is a global center of excellence in astronomy and astrophysics, attracting scientists from around the world (with English as its working language). It also promotes basic research in China with the highest international standards and carries out research on the origin and evolution of astrophysical structures from the scales of planetary systems and stars up to that of the Universe as a whole.

    The program of KIAA focuses on studies in three major areas of astrophysics:

    Cosmology, first light and galaxy assemblage;
    Gravitational physics and high-energy phenomena;
    Interstellar medium, stars and planets.

  • richardmitnick 2:14 pm on January 22, 2018 Permalink | Reply
    Tags: , , , CoRoT-2b, , Hot Jupiters,   

    From McGill: “A ‘hot Jupiter’ with unusual winds” 

    McGill University

    McGill University

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    Media Relations Office
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    McGill University/ McGill Space Institute

    Puzzling finding raises new questions about atmospheric physics of giant planets.

    Artist’s concept shows the gaseous exoplanet CoRoT-2b with a westward hot spot in orbit around its host star.
    CREDIT: NASA/JPL-Caltech/T. Pyle (IPAC).

    The hottest point on a gaseous planet near a distant star isn’t where astrophysicists expected it to be – a discovery that challenges scientists’ understanding of the many planets of this type found in solar systems outside our own.

    Unlike our familiar planet Jupiter, so-called hot Jupiters circle astonishingly close to their host star — so close that it typically takes fewer than three days to complete an orbit. And one hemisphere of these planets always faces its host star, while the other faces permanently out into the dark.

    Not surprisingly, the “day” side of the planets gets vastly hotter than the night side, and the hottest point of all tends to be the spot closest to the star. Astrophysicists theorize and observe that these planets also experience strong winds blowing eastward near their equators, which can sometimes displace the hot spot toward the east.

    In the mysterious case of exoplanet CoRoT-2b, however, the hot spot turns out to lie in the opposite direction: west of center. A research team led by astronomers at McGill University’s McGill Space Institute (MSI) and the Institute for research on exoplanets (iREx) in Montreal made the discovery using NASA’s Spitzer Space Telescope.

    NASA/Spitzer Infrared Telescope

    Their findings are reported Jan. 22 in the journal Nature Astronomy.

    Wrong-way wind

    “We’ve previously studied nine other hot Jupiter, giant planets orbiting super close to their star. In every case, they have had winds blowing to the east, as theory would predict,” says McGill astronomer Nicolas Cowan, a co-author on the study and researcher at MSI and iREx. “But now, nature has thrown us a curveball. On this planet, the wind blows the wrong way. Since it’s often the exceptions that prove the rule, we are hoping that studying this planet will help us understand what makes hot Jupiters tick.”

    CoRoT-2b, discovered a decade ago by a French-led space observatory mission, is 930 light years from Earth. While many other hot Jupiters have been detected in recent years, CoRoT-2b has continued to intrigue astronomers because of two factors: its inflated size and the puzzling spectrum of light emissions from its surface.

    “Both of these factors suggest there is something unusual happening in the atmosphere of this hot Jupiter,” says Lisa Dang, a McGill PhD student and lead author of the new study. By using Spitzer’s Infrared Array Camera to observe the planet while it completed an orbit around its host star, the researchers were able to map the planet’s surface brightness for the first time, revealing the westward hot spot.

    New questions

    The researchers offer three possible explanations for the unexpected discovery – each of which raises new questions:

    The planet could be spinning so slowly that one rotation takes longer than a full orbit of its star; this could create winds blowing toward the west rather than the east – but it would also undercut theories about planet-star gravitational interaction in such tight orbits.

    The planet’s atmosphere could be interacting with the planet’s magnetic field to modify its wind pattern; this could provide a rare opportunity to study an exoplanet’s magnetic field.

    Large clouds covering the eastern side of the planet could make it appear darker than it would otherwise – but this would undercut current models of atmospheric circulation on such planets.

    “We’ll need better data to shed light on the questions raised by our finding,” Dang says. “Fortunately, the James Webb Space Telescope, scheduled to launch next year, should be capable of tackling this problem. Armed with a mirror that has 100 times the collecting power of Spitzer’s, it should provide us with exquisite data like never before.”

    Scientists from the University of Michigan, the California Institute of Technology, Arizona State University, New York University Abu Dhabi, the University of California, Santa Cruz, and Pennsylvania State University also contributed to the study.

    See the full article here .

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    All about McGill

    With some 300 buildings, more than 38,500 students and 250,000 living alumni, and a reputation for excellence that reaches around the globe, McGill has carved out a spot among the world’s greatest universities.
    Founded in Montreal, Quebec, in 1821, McGill is a leading Canadian post-secondary institution. It has two campuses, 11 faculties, 11 professional schools, 300 programs of study and some 39,000 students, including more than 9,300 graduate students. McGill attracts students from over 150 countries around the world, its 8,200 international students making up 21 per cent of the student body.

  • richardmitnick 10:33 pm on November 27, 2017 Permalink | Reply
    Tags: , , , , Hot Jupiters, , , Newly Discovered Twin Planets Could Solve Puffy Planet Mystery, University of Hawaii Institute for Astronomy   

    From Keck: “Newly Discovered Twin Planets Could Solve Puffy Planet Mystery” 

    Keck Observatory

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

    Keck Observatory

    November 27, 2017
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    Upper left: Schematic of the K2-132 system on the main sequence. Lower left: Schematic of the K2-132 system now. The host star has become redder and larger, irradiating the planet more and thus causing it to expand. Sizes not to scale. Main panel: Gas giant planet K2-132b expands as its host star evolves into a red giant. The energy from the host star is transferred from the planet’s surface to its deep interior, causing turbulence and deep mixing in the planetary atmosphere. The planet orbits its star every nine days and is located about 2000 light years away from us in the constellation Virgo.
    Hot Jupiters. Credit: KAREN TERAMURA, UH ©IFA/Hawaii.

    Since astronomers first measured the size of an extrasolar planet seventeen years ago, they have struggled to answer the question: how did the largest planets get to be so large?

    Thanks to the recent discovery of twin planets by a University of Hawaii Institute for Astronomy team led by graduate student Samuel Grunblatt, scientists are getting closer to an answer.

    Gas giant planets are primarily made out of hydrogen and helium, and are at least four times the diameter of Earth. Gas giant planets that orbit scorchingly close to their host stars are known as “hot Jupiters.” These planets have masses similar to Jupiter and Saturn, but tend to be much larger – some are puffed up to sizes even larger than the smallest stars.

    The unusually large sizes of these planets are likely related to heat flowing in and out of their atmospheres, and several theories have been developed to explain this process. “However, since we don’t have millions of years to see how a particular planetary system evolves, planet inflation theories have been difficult to prove or disprove,” said Grunblatt.

    To solve this issue, Grunblatt searched through data collected by NASA’s K2 Mission to hunt for hot Jupiters orbiting red giant stars. These stars, which are in the late stages of their lives, become themselves significantly larger over their companion planet’s lifetime. Following a theory put forth by Eric Lopez of NASA’s Goddard Space Flight Center, hot Jupiters orbiting red giant stars should be highly inflated if direct energy input from the host star is the dominant process inflating planets.

    The search has now revealed two planets, each orbiting their host star with a period of approximately nine days. Using stellar oscillations to precisely calculate the radii of both the stars and planets, the team found that the planets are 30 percent larger than Jupiter.

    Observations using the W. M. Keck Observatory on Maunakea, Hawaii also showed that, despite their large sizes, the planets were only half as massive as Jupiter. Remarkably, the two planets are near twins in terms of their orbital periods, radii, and masses.

    Using models to track the evolution of the planets and their stars over time, the team calculated the planets’ efficiency at absorbing heat from the star and transferring it to their deep interiors, causing the whole planet to expand in size and decrease in density. Their findings show that these planets likely needed the increased radiation from the red giant star to inflate, but the amount of radiation absorbed was also lower than expected.

    It is risky to attempt to reach strong conclusions with only two examples. But these results begin to rule out some explanations of planet inflation, and are consistent with a scenario where planets are directly inflated by the heat from their host stars. The mounting scientific evidence seems to suggest that stellar radiation alone can directly alter the size and density of a planet.

    Our own Sun will eventually become a red giant star, so it’s important to quantify the effect its evolution will have on the rest of the Solar System. “Studying how stellar evolution affects planets is a new frontier, both in other solar systems as well as our own,” said Grunblatt. “With a better idea of how planets respond to these changes, we can start to determine how the Sun’s evolution will affect the atmosphere, oceans, and life here on Earth.”

    The search for gas giant planets around red giant stars continues since additional systems could conclusively distinguish between planet inflation scenarios. Grunblatt and his team have been awarded time with the NASA Spitzer Space Telescope to measure the sizes of these twin planets more accurately. In addition, the search for planets around red giants with the NASA K2 Mission will continue for at least another year, and NASA’s Transiting Exoplanet Survey Satellite (TESS), launching in 2018, will observe hundreds of thousands of red giants across the entire sky.

    Seeing double with K2: Testing re-inflation with two remarkably similar planets orbiting red giant branch stars. published in November 27th edition of The Astronomical Journal.

    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 2:11 pm on August 2, 2017 Permalink | Reply
    Tags: , , , , Hot Jupiters, Hubble Detects Exoplanet with Glowing Water Atmosphere, , WASP121b   

    From Hubble: “Hubble Detects Exoplanet with Glowing Water Atmosphere” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    Aug 2, 2017

    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, California

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland

    Scorching “Hot Jupiter” Has a Stratospheric Layer
    Only when we fly in a commercial jet at an altitude of about 33,000 feet do we enter Earth’s stratosphere, a cloudless layer of our atmosphere that blocks ultraviolet light. Astronomers were fascinated to find evidence for a stratosphere on a planet orbiting another star. As on Earth, the planet’s stratosphere is a layer where temperatures increase with higher altitudes, rather than decrease. However, the planet (WASP-121b) is anything but Earth-like. The Jupiter-sized planet is so close to its parent star that the top of the atmosphere is heated to a blazing 4,600 degrees Fahrenheit (2,500 degrees Celsius), hot enough to rain molten iron! This new Hubble Space Telescope observation allows astronomers to compare processes in exoplanet atmospheres with the same processes that happen under different sets of conditions in our own solar system.

    Scientists have discovered the strongest evidence to date for a stratosphere on a planet outside our solar system, or exoplanet. A stratosphere is a layer of atmosphere in which temperature increases with higher altitudes.

    “This result is exciting because it shows that a common trait of most of the atmospheres in our solar system — a warm stratosphere — also can be found in exoplanet atmospheres,” said Mark Marley, study co-author based at NASA’s Ames Research Center in California’s Silicon Valley. “We can now compare processes in exoplanet atmospheres with the same processes that happen under different sets of conditions in our own solar system.”

    Reporting in the journal Nature, scientists used data from NASA’s Hubble Space Telescope to study WASP-121b, a type of exoplanet called a “hot Jupiter.” Its mass is 1.2 times that of Jupiter, and its radius is about 1.9 times Jupiter’s — making it puffier. But while Jupiter revolves around our sun once every 12 years, WASP-121b has an orbital period of just 1.3 days. This exoplanet is so close to its star that if it got any closer, the star’s gravity would start ripping it apart. It also means that the top of the planet’s atmosphere is heated to a blazing 4,600 degrees Fahrenheit (2,500 degrees Celsius), hot enough to boil some metals. The WASP-121 system is estimated to be about 900 light-years from Earth — a long way, but close by galactic standards.

    Previous research found possible signs of a stratosphere on the exoplanet WASP-33b as well as some other hot Jupiters. The new study presents the best evidence yet because of the signature of hot water molecules that researchers observed for the first time.

    “Theoretical models have suggested stratospheres may define a distinct class of ultra-hot planets, with important implications for their atmospheric physics and chemistry,” said Tom Evans, lead author and research fellow at the University of Exeter, United Kingdom. “Our observations support this picture.”

    To study the stratosphere of WASP-121b, scientists analyzed how different molecules in the atmosphere react to particular wavelengths of light, using Hubble’s capabilities for spectroscopy. Water vapor in the planet’s atmosphere, for example, behaves in predictable ways in response to certain wavelengths of light, depending on the temperature of the water.

    Starlight is able to penetrate deep into a planet’s atmosphere, where it raises the temperature of the gas there. This gas then radiates its heat into space as infrared light. However, if there is cooler water vapor at the top of the atmosphere, the water molecules will prevent certain wavelengths of this light from escaping to space. But if the water molecules at the top of the atmosphere have a higher temperature, they will glow at the same wavelengths.

    “The emission of light from water means the temperature is increasing with height,” said Tiffany Kataria, study co-author based at NASA’s Jet Propulsion Laboratory, Pasadena, California. “We’re excited to explore at what longitudes this behavior persists with upcoming Hubble observations.”

    The phenomenon is similar to what happens with fireworks, which get their colors from chemicals emitting light. When metallic substances are heated and vaporized, their electrons move into higher energy states. Depending on the material, these electrons will emit light at specific wavelengths as they lose energy: sodium produces orange-yellow and strontium produces red in this process, for example. The water molecules in the atmosphere of WASP-121b similarly give off radiation as they lose energy, but in the form of infrared light, which the human eye is unable to detect.

    In Earth’s stratosphere, ozone gas traps ultraviolet radiation from the sun, which raises the temperature of this layer of atmosphere. Other solar system bodies have stratospheres, too; methane is responsible for heating in the stratospheres of Jupiter and Saturn’s moon Titan, for example.

    In solar system planets, the change in temperature within a stratosphere is typically around 100 degrees Fahrenheit (about 56 degrees Celsius). On WASP-121b, the temperature in the stratosphere rises by 1,000 degrees (560 degrees Celsius). Scientists do not yet know what chemicals are causing the temperature increase in WASP-121b’s atmosphere. Vanadium oxide and titanium oxide are candidates, as they are commonly seen in brown dwarfs, “failed stars” that have some commonalities with exoplanets. Such compounds are expected to be present only on the hottest of hot Jupiters, as high temperatures are needed to keep them in a gaseous state.

    “This super-hot exoplanet is going to be a benchmark for our atmospheric models, and it will be a great observational target moving into the Webb era,” said Hannah Wakeford, study co-author who worked on this research while at NASA’s Goddard Space Flight Center, Greenbelt, Maryland.

    See the full article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 11:49 am on July 7, 2017 Permalink | Reply
    Tags: , , , Hot Jupiters,   

    From Yale: “A cosmic barbecue: Researchers spot 60 new ‘hot Jupiter’ candidates” 

    Yale University bloc

    Yale University

    July 6, 2017

    Jim Shelton


    Yale researchers have identified 60 potential new “hot Jupiters” — highly irradiated worlds that glow like coals on a barbecue grill and are found orbiting only 1% of Sun-like stars.

    Hot Jupiters constitute a class of gas giant planets located so close to their parent stars that they take less than a week to complete an orbit.

    Second-year Ph.D. student Sarah Millholland and astronomy professor Greg Laughlin identified the planet candidates via a novel application of big data techniques. They used a supervised machine learning algorithm — a sophisticated program that can be trained to recognize patterns in data and make predictions — to detect the tiny amplitude variations in observed light that result as an orbiting planet reflects rays of light from its host star.

    Millholland recently presented the research at a Kepler Science Conference at the NASA Ames Research Center in California. She and Laughlin are authors of a study about the research, which has been accepted for publication in the Astronomical Journal.

    The Yale technique pioneers a new discovery method that identifies more planets from the publicly available Kepler data, said the researchers.

    The Doppler velocity method is a well-established technique that enables the detection of wobbling motion in a star due to the gravitational influence of an orbiting planet. Since hot Jupiters are so massive and close to their stars, the stellar wobbles they induce are large and readily detectable.

    A new, Yale-designed instrument known as EXPRES, which is being installed on the Discovery Channel Telescope in Arizona, may attempt to make confirmations later this year.

    NSF funded Extreme Precision Spectrograph, EXPRES. The spectrograph will be commissioned at the Discovery Channel Telescope, part of the Lowell Observatory, near Flagstaff, Arizona

    Discovery Channel Telescope at Lowell Observatory, Happy Jack AZ, USA

    See the full article here .

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    Yale University Campus

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

  • richardmitnick 7:00 am on June 15, 2017 Permalink | Reply
    Tags: , , , , Clouds over the sunlit arch, , Hot Jupiters, WASP-12 b   

    From astrobites: “Clouds over the sunlit arch” 

    Astrobites bloc


    Jun 15, 2017
    Eckhart Spalding

    Title: High-temperature condensate clouds in super-hot Jupiter atmospheres
    Authors: H.R. Wakeford, C. Visscher, N.K. Lewis, T. Kataria, M.S. Marley, J.J. Fortney, A.M. Mandell
    First Author’s Institution: Planetary Systems Lab, NASA Goddard Space Flight Center

    Status: Published in MNRAS [open access]


    Having grown up on Earth, we tend to associate cloudy skies with brisk weather. Even gloomy weather. As Robert Frost said, if it’s the month of May and a “cloud comes over the sunlit arch” you’ll find yourself “two months back in the middle of March”. How different are clouds on alien worlds? Is there such a thing as searingly hot clouds, suspended high above in skies so bright they make your eyes ache when you shut them tight?

    If we want to study alien clouds outside our own solar system, “hot Jupiter” planets are our best test subjects. Hot Jupiters are gas giant planets which orbit very close to their host stars. Their atmospheres are relatively easy to characterize if they pass directly in front of their host star [transit], which allows light from the host star to pass through their extended atmospheres and provide us with transmission spectra.

    Planet transit. NASA/Ames

    In this light (no pun intended), the physics of clouds have experienced a recent surge of interest in the exoplanet field. Clouds play critical roles in an atmosphere’s energy balance: they can reflect light back into space, trap heat, remove absorbing compounds, influence wind structure and chemical reaction times, and exert feedback effects on atmospheric temperature-pressure profiles. Clouds also complicate measurements of chemical abundances, because clouds tend to dampen absorption features and can transmit photons as an unknown function of wavelength. (Remember when you got sunburned on a cloudy day?)

    Clouds in exoplanet atmospheres are a little bit like turbulence or magnetic fields in star formation– they add a rich level of physics to what would otherwise be a much simpler physical picture. But the first strong evidence of thick cloud decks on exoplanets dates only from 2014, and we still don’t know much about the nature of those clouds. (In fact we’re still working on Earth clouds. Earth is, after all, a little-known planet.)

    Today’s paper

    The authors of today’s paper push the boundaries of knowledge into the most scalding area of parameter space: the realm of sizzling “super-hot” Jupiters, with temperatures of more than 1800 K. Part of the authors’ motivation is to address a longstanding puzzle. The temperature in most planetary atmospheres should become colder at higher altitudes. But according to models, hot Jupiters with very high incident flux levels are expected to harbor high-altitude atmospheric absorbers like TiO or VO. If these compounds are present, they will cause a “temperature inversion” where temperature actually rises with altitude. Strangely, however, these compounds or temperature inversions have been difficult to find in hot Jupiters.

    Fig. 1: The transmission spectrum of WASP-12 b. The y-axis represents the effective “thickness” of the atmosphere at a certain wavelength. Actual data are in the form of black data points, and pure condensate curves are in orange and green. The relative flatness on the left side of the plot indicates the presence of clouds. Before the James Webb Space Telescope (JWST) fills in the right side of this plot, the condensate models cannot be well distinguished. (Fig. 5 from today’s paper.)

    NASA/ESA/CSA Webb Telescope annotated

    The authors begin by considering the hottest condensates that may exist in a hot Jupiter atmosphere: calcium (Ca), titanium (Ti), and aluminum (Al). They assume cloud formation occurs when rising air reaches vapor pressure saturation, and that clouds stop forming when one of the constituent elements is depleted. They calculate the resulting relative cloud masses, play around with the atmospheric metallicities, and overlay temperature-pressure curves on condensation curves to see what types of clouds should form. Among their findings, Al compounds will form much more cloud material than Ti, and higher atmospheric metallicity levels allow the formation of more massive clouds.

    The authors turn to the specific case of the planet WASP-12 b. The transmission spectrum of WASP-12 b exhibits some water absorption but is otherwise fairly flat, which indicates the presence of clouds.

    Fig. 2: Left: Solid colored lines represent temperature-pressure curves in different regions of WASP-12 b.

    Hubble Finds a Star Eating a Planet. Artist’s concept of the exoplanet WASP-12b. Credit: NASA/ESA/G. Bacon

    NASA/ESA Hubble Telescope

    Dashed lines represent condensation curves for different compounds. Clouds will form between the temperature-pressure and condensation curves. For example, iron (Fe) clouds will exist on the night side at altitudes corresponding to pressures in bars (P) below log(P) = -1.5. Pressures accessible to transmission spectroscopy are between about log(P) of -1 to -4. (Note that pressure decreases as the y-axis increases.) Right: An alternative representation showing the effect of distance from the substellar point. Clouds will form on the nightside side of the lines. Vertical dashed lines show the regions between day and night sides probed by transmission spectroscopy. (Fig. 4 from today’s paper.)

    After doing some more model calculations, the authors overlay condensation curves on a 2D plot of temperature as a function of pressure and longitude. Interestingly, the clouds roasting in WASP-12 b’s atmosphere start to form right around the regions accessible to transit spectroscopy. At temperatures of less than 1900 K, WASP-12 b’s clouds can shroud the signatures of TiO or “hide” its constituents via condensation.

    There still is much work to be done in understanding clouds among the worlds that “favor fire“. Condensation nuclei and condensate growth are very poorly constrained, and more lab work is needed to determine the optics of different compounds. But there is light on the horizon (again no pun intended). Certain absorption bands including Ti-O vibrations are within the discovery space of JWST, which may allow us to distinguish between WASP 12 b clouds which hide TiO or remove Ti from the gas phase.

    That would bring us full circle: after predicting the compositions of clouds on super-hot Jupiters, today’s paper has left us with a test observation to disentangle the effect of clouds on WASP-12 b. That test will get us another step towards resolving the mystery of the missing thermal inversions.

    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 6:01 pm on June 5, 2017 Permalink | Reply
    Tags: , , , , , HAT-P-38 b, Hot Jupiters, , WASP-67 b   

    From Hubble: “Hubble’s Tale of Two Exoplanets: Nature vs. Nurture” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    Release type: American Astronomical Society Meeting

    Atmospheres of Two Hot Jupiters: Cloudy and Clear

    Astronomers once thought that the family of planets that orbit our sun were typical of what would eventually be found around other stars: a grouping of small rocky planets like Earth huddled close to their parent star, and an outer family of monstrous gaseous planets like Jupiter and Saturn.

    But ever since the discovery of the first planet around another star (or exoplanet) the universe looks a bit more complicated — if not downright capricious. There is an entire class of exoplanets called “hot Jupiters.” They formed like Jupiter did, in the frigid outer reaches of their planetary system, but then changed Zip code! They migrated inward to be so close to their star that temperatures are well over 1,000 degrees Fahrenheit.

    Astronomers would like to understand the weather on these hot Jupiters and must tease out atmospheric conditions by analyzing how starlight filters through a planet’s atmosphere. If the spectral fingerprint of water can be found, then astronomers conclude the planet must have relatively clear skies that lets them see deep into the atmosphere. If the spectrum doesn’t have any such telltale fingerprints, then the planet is bland-looking with a high cloud deck.

    Knowing the atmospheres on these distant worlds yields clues to how they formed and evolved around their parent star. In a unique experiment, astronomers aimed the Hubble Space Telescope at two “cousin” hot Jupiters that are similar in several respects. However, the researchers were surprised to learn that one planet is very cloudy, and the other has clear skies.

    The Full Story
    Ann Jenkins
    Space Telescope Science Institute, Baltimore, Maryland

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland

    Giovanni Bruno
    Space Telescope Science Institute, Baltimore, Maryland


    Is it a case of nature versus nurture when it comes to two “cousin” exoplanets? In a unique experiment, scientists used NASA’s Hubble Space Telescope to study two “hot Jupiter” exoplanets. Because these planets are virtually the same size and temperature, and orbit around nearly identical stars at the same distance, the team hypothesized that their atmospheres should be alike. What they found surprised them.

    Lead researcher Giovanni Bruno of the Space Telescope Science Institute in Baltimore, Maryland, explained, “What we’re seeing in looking at the two atmospheres is that they’re not the same. One planet—WASP-67 b—is cloudier than the other—HAT-P-38 b. We don’t see what we’re expecting, and we need to understand why we find this difference.”

    The team used Hubble’s Wide Field Camera 3 to look at the planets’ spectral fingerprints, which measure chemical composition.

    NASA/ESA Hubble WFC3

    “The effect that clouds have on the spectral signature of water allows us to measure the amount of clouds in the atmosphere,” Bruno said. “More clouds mean that the water feature is reduced.” The teams found that for WASP-67 b there are more clouds at the altitudes probed by these measurements.

    “This tells us that there had to be something in their past that is changing the way these planets look,” said Bruno.

    Today the planets whirl around their yellow dwarf stars once every 4.5 Earth days, tightly orbiting their stars closer than Mercury orbits our sun. But in the past, the planets probably migrated inward toward the star from the locations where they formed.

    Perhaps one planet formed differently than the other, under a different set of circumstances. “You can say it’s nature versus nurture,” explains co-investigator Kevin Stevenson. “Right now, they appear to have the same physical properties. So, if their measured composition is defined by their current state, then it should be the same for both planets. But that’s not the case. Instead, it looks like their formation histories could be playing an important role.”

    The clouds on these hot, Jupiter-like gas giants are nothing like those on Earth. Instead, they are probably alkali clouds, composed of molecules such as sodium sulfide and potassium chloride. The average temperature on each planet is more than 1,300 degrees Fahrenheit.

    The exoplanets are tidally locked, with the same side always facing the parent star. This means they have a very hot day-side and a cooler night-side. Instead of sporting multiple cloud bands like Jupiter does, each probably has just one broad equatorial band that slowly moves the heat around from the day-side to the night-side.

    The team is just beginning to learn what factors are important in making some exoplanets cloudy and some clear. To better understand what the planets’ pasts may have been, scientists will need future observations with Hubble and the soon-to-be-launched James Webb Space Telescope.

    The team’s results were presented on June 5 at the 230th meeting of the American Astronomical Society in Austin, Texas.

    The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

    Illustration: NASA, ESA, and Z. Levy (STScI)
    Science: NASA, ESA, and G. Bruno (STScI)

    See the full article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 12:36 pm on April 18, 2017 Permalink | Reply
    Tags: , , Hot Jupiters   

    From AAS NOVA: “Samples and Statistics: Distinguishing Populations of Hot Jupiters in a Growing Dataset” 


    American Astronomical Society


    18 April 2017
    Jamila Pegues

    Title: Evidence for Two Hot Jupiter Formation Paths
    Authors: Benjamin E. Nelson, Eric B. Ford, and Frederic A. Rasio
    First Author’s Institution: Northwestern University

    Status: Submitted to AJ, open access

    Figure 1: A gorgeous artist’s impression of a hot Jupiter orbiting around its host star. [ESO/L. Calçada]

    Frolicking Through Fields of Data

    The future of astronomy observations seems as bright as the night sky … and just as crowded! Over the next decade, several truly powerful telescopes are set to launch (read about a good number of them here and also here).


    Giant Magellan Telescope, Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile

    TMT-Thirty Meter Telescope, proposed for Mauna Kea, Hawaii, USA

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile

    LSST Camera, built at SLAC

    LSST telescope, currently under construction at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    NASA/ESA/CSA Webb Telescope annotated


    FAST radio telescope, now operating, located in the Dawodang depression in Pingtang county Guizhou Province, South China

    That means we’re going to have a LOT of data on everything from black holes to galaxies, and beyond — and that’s in addition to the huge fields of data from the past decade that we’re already frolicking through now. It’s certainly far more data than any one astronomer (or even a group of astronomers) wants to analyze one-by-one; that’s why these days, astronomers turn more and more to the power of astrostatistics to characterize their data.

    The authors of today’s astrobite had that goal in mind. They explored a widely-applicable, data-driven statistical method for distinguishing different populations in a sample of data. In a sentence, they took a large sample of hot Jupiters and used this technique to try and separate out different populations of hot Jupiters — based on how the planets were formed — within their sample. Let’s break down exactly what they did, and how they did it, in the next few sections!

    Hot Jupiters Are Pretty Cool

    First question: what’s a hot Jupiter, anyway?

    They’re actually surprisingly well-named: essentially, they are gas-giant planets like Jupiter, but are much, much hotter. (Read all about them in previous astrobites, like this one and this other one!) Hot Jupiters orbit perilously close to their host stars — closer even than Mercury does in our own Solar System, for example. But it seems they don’t start out there. It’s more likely that these hot Jupiters formed out at several AU from their host stars, and then migrated inward into the much closer orbits from there.

    As to why hot Jupiters migrate inward … well, it’s still unclear. Today’s authors focused on two migration pathways that could lead to two distinct populations of hot Jupiters in their sample. These migration theories, as well as what the minimum allowed distance to the host star (the famous Roche separation distance, aRoche) would be in each case, are as follows:

    Disk migration: hot Jupiters interact with their surrounding protoplanetary disk, and these interactions push their orbits inward. In this context, aRoche corresponds to the minimum distance that a hot Jupiter could orbit before its host star either (1) stripped away all of the planet’s gas or (2) ripped the planet apart.
    Eccentric migration: hot Jupiters start out on very eccentric (as in, more elliptical than circular) orbits, and eventually their orbits morph into circular orbits of distance 2aRoche. In this context, aRoche refers to the minimum distance that a hot Jupiter could orbit before the host star pulled away too much mass from the planet.

    The authors defined a parameter ‘x’ for a given hot Jupiter to be x = a/aRoche, where ‘a’ is the planet’s observed semi-major axis. Based on the minimum distances in the above theories, we could predict that hot Jupiters that underwent disk migration would have a minimum x-value of x = aRoche/aRoche = 1. On the other hand, hot Jupiters that underwent eccentric migration would instead have a minimum x-value of x = 2aRoche/aRoche = 2. This x for a given planet is proportional to the planet’s orbital period ‘P’, its radius ‘R’, and its mass ‘M’ in the following way:

    And this x served as a key parameter in the authors’ statistical models!

    Toying with Bayesian Statistics

    Next question: how did today’s authors statistically model their data?

    Figure 2: Probability distribution of x for each observation group, assuming that each hot Jupiter orbit was observed along the edge (like looking at the thin edge of a DVD). The bottom panel zooms in on the top one. Note how the samples have different minimum values! [Nelson et al. 2017]

    Short answer: with Bayesian statistics. Basically, the authors modeled how the parameter x is distributed within their planet sample with truncated power laws — so, x raised to some power, cut off between minimum and maximum x values. They split their sample of planets into two groups, based on the telescope and technique used to observe the planets: “RV+Kepler” and “HAT+WASP”. Figure 2 displays the distribution of x for each of the subgroups.

    The authors then used the Markov Chain Monte Carlo method (aka, MCMC; see the Bayesian statistics link above) to explore what sort of values of the power laws’ powers and cutoffs would well represent their data. Based on their chosen model form, they found that the RV+Kepler sample fit well with their model relating to eccentric migration. On the other hand, they found evidence that the HAT+WASP sample could be split into two populations: about 15% of those planets corresponded to disk migration, while the other 85% or so corresponded to eccentric migration.

    Remember that a major goal of today’s authors was to see if they could use this statistical approach to distinguish between planet populations in their sample … and in that endeavor, they were successful! The authors were thus optimistic about using this statistical technique for a much larger sample of hot Jupiters in the future, as oodles of data stream in from telescopes and surveys like KELT, TESS, and WFIRST over the next couple of decades.

    Their success joins the swelling toolbox of astrostatistics … and just in time! Telescopes of the present and very-near future are going to flood our computers with data — so unless we’re willing to examine every bright spot we observe in the sky by hand, we’ll need all the help from statistics that we can get!

    See the full article here .

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