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  • richardmitnick 7:12 am on February 8, 2016 Permalink | Reply
    Tags: , Exoplanets,   

    From New Scientist: “How Do You Find an Exoplanet? An insider account gives top tips” 


    New Scientist

    3 February 2016
    Lewis Dartnell

    Soon, Chile’s giant telescope will search for Earth-like exoplanets ESO/S. Bruner

    ASTRONOMY has changed a lot in the days since you had to go and sit for hours with your eyeball at the focal point of a 5-metre-diameter telescope atop a mountain.

    This is quickly evident in How Do You Find an Exoplanet? by John Asher Johnson, formerly a leading researcher at NASA. In 2012, his team discovered three exoplanets orbiting a red dwarf, including the smallest found to date. Now a professor at Harvard University, Johnson’s enthusiasm for his vibrant field is palpable in this valuable, concise guide for amateur astronomers and anyone else not afraid of a few technicalities.

    Today, telescopes are controlled from a computer in a heated room. We have also lived through a revolution in our understanding of the cosmos. At the time of writing, we have discovered 2042 worlds orbiting other stars. This is one of the hottest areas in current research, with new finds making headlines almost weekly.

    Since these remote planets are vanishingly dim alongside the overwhelming glare of their host stars, how do we find them? Johnson rattles through the astronomers’ main tricks. The two most successful techniques involve measuring the radial velocity, or wobble, of a star as it is tugged by an orbiting planet, and registering the minuscule dimming of starlight as a planet transits across the face of a star.

    We are also getting good at capturing images of exoplanets alongside their stars. And then there is microlensing, where an exoplanet is detected by the way its gravity focuses the light of a distant background star. [Albert] Einstein’s general theory of relativity predicts this effect, but attempts to apply it to astronomy were abandoned in 1936 because of the limits of photographic plate technology at the time.

    The greatest value of reading an “insider” book, though, is the insight the author can give us into what we can expect in the near future. For my money, the most exciting discoveries will come from ESPRESSO – a particularly apt acronym for this nocturnal profession – which stands for Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations.

    ESO Espresso
    Espresso in the clean room

    This ultra-high-resolution spectrometer will soon be installed in the [ESO] Very Large Telescope in northern Chile, where it will simultaneously harness the light-gathering capabilities of four huge 8.2- metre telescopes. By measuring the wobble of a targeted star down to a velocity of just 10 centimetres per second, ESPRESSO will be able to detect Earth-like planets in the habitable zone of their star.

    As those headlines about new exoplanets increase, after reading this book, you will be able to say you predicted as much.

    How Do You Find an Exoplanet?
    John Asher Johnson
    Princeton University Press

    See the full article here .

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  • richardmitnick 9:48 am on January 17, 2016 Permalink | Reply
    Tags: , , , Exoplanets   

    From ESO: ESOCast 79 – 20 Years of Exoplanets 

    European Southern Observatory

    Published on Dec 8, 2015

    Not a single confirmed planet outside the Solar System had been detected before the year 1990. But, remarkably, we now know of thousands and have studied many in surprising detail. This ESOcast takes a look at how ESO’s observatories in Chile have been at the forefront of this enormous expansion in knowledge, and how their state-of-the-art instruments are continuing to discover and study the extraordinary diversity of exoplanets.

    Watch, enjoy, learn.

    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 VLT Interferometer

    ESO Vista Telescope


    ESO VLT Survey telescope
    VLT Survey Telescope

    ALMA Array


    Atacama Pathfinder Experiment (APEX) Telescope

  • richardmitnick 9:49 am on January 15, 2016 Permalink | Reply
    Tags: , , , Exoplanets   

    From Daily Galaxy: “”Nixing 100 Billion Galaxies” –Bayesian Reasoning Dismisses Existence of Alien Life” 

    Daily Galaxy
    The Daily Galaxy

    January 14, 2016
    No writer credit found

    Temp 1
    Image credits: NASA/ESA/IAC/HFF Team, STScI

    Carl Sagan said that “extraordinary claims, require extraordinary evidence.” In a stunning display of mathematical logic, David Spiegel of Princeton University and Edwin Turner from the University of Tokyo published a paper in 2012 that turns the Drake equation upside down using Bayesian reasoning to show that just because we evolved on Earth, doesn’t mean that the same occurrence would necessarily happen elsewhere; “using evidence of our own existence doesn’t show anything” they argue, “other than that we are here.”
    The recent Kepler Space-Telescope discoveries of planets similar to Earth in size and proximity to the planets’ respective suns have sparked scientific and public excitement about the possibility of also finding Earth-like life on those worlds.

    NASA Kepler Telescope

    But the Princeton University researchers have found that the expectation that life — from bacteria to sentient beings — has or will develop on other planets as on Earth might be based more on optimism than scientific evidence.

    Astrophysical sciences professor Turner and lead author Spiegel analyzed what is known about the likelihood of life on other planets in an effort to separate the facts from the mere expectation that life exists outside of Earth. The researchers used a Bayesian analysis — which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist — to determine the probability of extraterrestrial life once the influence of these presumptions is minimized.

    Turner and Spiegel, who is now at the Institute for Advanced Study, argued in the Proceedings of the National Academy of Sciences [no link to paper] that the idea that life has or could arise in an Earth-like environment has only a small amount of supporting evidence, most of it extrapolated from what is known about abiogenesis, or the emergence of life, on early Earth. Instead, their analysis showed that the expectations of life cropping up on exoplanets — those found outside Earth’s solar system — are largely based on the assumption that it would or will happen under the same conditions that allowed life to flourish on this planet.

    In fact, the researchers conclude, the current knowledge about life on other planets suggests that it’s very possible that Earth is a cosmic aberration where life took shape unusually fast. If so, then the chances of the average terrestrial planet hosting life would be low.

    “Fossil evidence suggests that life began very early in Earth’s history and that has led people to determine that life might be quite common in the universe because it happened so quickly here, but the knowledge about life on Earth simply doesn’t reveal much about the actual probability of life on other planets,” Turner said.

    “Information about that probability comes largely from the assumptions scientists have going in, and some of the most optimistic conclusions have been based almost entirely on those assumptions,” he said.

    Turner and Spiegel used Bayes’ theorem to assign a sliding mathematical weight to the prior assumption that life exists on other planets. The “value” of that assumption was used to determine the probability of abiogenesis, in this case defined as the average number of times that life arises every billion years on an Earth-like planet. Turner and Spiegel found that as the influence of the assumption increased, the perceived likelihood of life existing also rose, even as the basic scientific data remained the same.

    “If scientists start out assuming that the chances of life existing on another planet as it does on Earth are large, then their results will be presented in a way that supports that likelihood,” Turner said. “Our work is not a judgment, but an analysis of existing data that suggests the debate about the existence of life on other planets is framed largely by the prior assumptions of the participants.”

    Joshua Winn, an associate professor of physics at the Massachusetts Institute of Technology, said that Turner and Spiegel cast convincing doubt on a prominent basis for expecting extraterrestrial life. Winn, who focuses his research on the properties of exoplanets, is familiar with the research but had no role in it.

    “There is a commonly heard argument that life must be common or else it would not have arisen so quickly after the surface of the Earth cooled,” Winn said. “This argument seems persuasive on its face, but Spiegel and Turner have shown it doesn’t stand up to a rigorous statistical examination — with a sample of only one life-bearing planet, one cannot even get a ballpark estimate of the abundance of life in the universe.

    “I also have thought that the relatively early emergence of life on Earth gave reasons to be optimistic about the search for life elsewhere,” Winn said. “Now I’m not so sure, though I think scientists should still search for life on other planets to the extent we can.”

    Deep-space satellites and telescope projects have recently identified various planets that resemble Earth in their size and composition, and are within their star’s habitable zone, the optimal distance for having liquid water.

    Of particular excitement have been the discoveries of NASA’s Kepler Space Telescope. In December 2011, NASA announced the first observation of Kepler-22b, a planet 600 light years from Earth and the first found within the habitable zone of a Sun-like star.

    Temp 3
    Kepler-22b — Comfortably Circling within the Habitable Zone.This diagram compares our solar system to Kepler-22, a star system containing the first “habitable zone” planet discovered by NASA’s Kepler mission. The habitable zone is the spot around a star where temperatures are right for water to exist in its liquid form. Liquid water is essential for life on Earth.

    Kepler-22’s star is a bit smaller than our sun, so its habitable zone is slightly closer in. The diagram shows an artist’s rendering of the planet comfortably orbiting within the habitable zone, similar to where Earth circles the sun. Kepler-22b has a yearly orbit of 289 days. The planet is the smallest known to orbit in the middle of the habitable zone of a sun-like star. It’s about 2.4 times the size of Earth.
    Image credit: NASA/Ames/JPL-Caltech
    Date 5 December 2011

    Weeks later, NASA reported Keplers-20e and -20f, the first Earth-sized planets found orbiting a Sun-like star. NASA has since announced the discovery of over 2000 Kepler planets, with some 500 possible Earth-like candidates.

    While these observations tend to stoke the expectation of finding Earth-like life, they do not actually provide evidence that it does or does not exist, Spiegel explained. Instead, these planets have our knowledge of life on Earth projected onto them, he said.

    Yet, when what is known about life on Earth is taken away, there is no accurate sense of how probable abiogenesis is on any given planet, Spiegel said. It was this “prior ignorance,” or lack of expectations, that he and Turner wanted to account for in their analysis, he said.

    “When we use a mathematical prior that truly represents prior ignorance, the data of early life on Earth becomes ambiguous,” Spiegel said.

    “Our analysis suggests that abiogenesis could be a rather rapid and probable process for other worlds, but it also cannot rule out at high confidence that abiogenesis is a rare, improbable event,” Spiegel said. “We really have no idea, even to within orders of magnitude, how probable abiogenesis is, and we show that no evidence exists to substantially change that.”

    Spiegel and Turner also propose that once this planet’s history is considered, the emergence of life on Earth might be so distinct that it is a poor barometer of how it occurred elsewhere, regardless of the likelihood that such life exists.

    In a philosophical turn, they suggest that because humans are the ones wondering about the emergence of life, it is possible that we must be on a planet where life began early in order to reach a point so soon after the planet’s formation 4.5 billion years ago where we could wonder about it.

    Thus, Spiegel and Turner explored how the probability of exoplanetary abiogenesis would change if it turns out that evolution requires, as it did on Earth, roughly 3.5 billion years for life to develop from its most basic form to complex organisms capable of pondering existence. If that were the case, then the 4.5 billion-year-old Earth clearly had a head start. A planet of similar age where life did not begin until several billion years after the planet formed would have only basic life forms at this point.

    “Dinosaurs and horseshoe crabs, which were around 200 million years ago, presumably did not consider the probability of abiogenesis. So, we would have to find ourselves on a planet with early abiogenesis to reach this point, irrespective of how probable this process actually is,” Spiegel said. “This evolutionary timescale limits our ability to make strong inferences about how probable abiogenesis is.”

    Turner added, “It could easily be that life came about on Earth one way, but came about on other planets in other ways, if it came about at all. The best way to find out, of course, is to look. But I don’t think we’ll know by debating the process of how life came about on Earth.”

    Again, said Winn of MIT, Spiegel and Turner offer a unique consideration for scientists exploring the possibility of life outside of Earth.

    “I had never thought about the subtlety that we as a species could never have ‘found’ ourselves on a planet with a late emergence of life if evolution takes a long time to produce sentience, as it probably does,” Winn said.

    “With that in mind,” he said, “it seems reasonable to say that scientists cannot draw any strong conclusion about life on other planets based on the early emergence of life on Earth.”

    What Bayesian reasoning overlooks, of course, is the inconvenient fact that there are some one trillion galaxies in the known universe and some 50 billion planets estimated to exist in the Milky Way alone and some 500,000,000 predicted to exist in a habitable zone. Spiegel and Turner point out that basing our expectations of life existing on other planets, for no better reason that it exists here, is really only proof that were are more than capable of deceiving ourselves into thinking that things are much more likely than they really are.

    NASA’s Hubble Space Telescope has picked up the faint, ghostly glow of stars ejected from ancient galaxies shown below that were gravitationally ripped apart several billion years ago. The mayhem happened 4 billion light-years away, inside an immense collection of nearly 500 galaxies nicknamed “Pandora’s Cluster,” also known as Abell 2744. The Hubble team estimates that the combined light of about 200 billion outcast stars contributes approximately 10 percent of the cluster’s brightness.

    Temp 2
    No image credit found

    NASA Hubble Telescope
    NASA/ESA Hubble

    They argue that other unknown factors exist that could have contributed to us being here that we don’t yet understand. So, they conclude that, deriving numbers from an equation such as that put forth by Drake, only serves to underscore our belief in the existence of other alien life forms, rather than the actual chances of it being so.

    We think evidence will be discovered in the next 20 years: The Kepler mission has discovered 1,235 exoplanets that revolve around a sun, in an area that represents around 1/400th of the Milky Way. By extrapolating these numbers, the Kepler team has estimated that there are at least 50 billion exoplanets in our galaxy — 500 million of which sit inside the habitable “Goldilocks” zones of their suns, the area that it is neither too hot nor too cold to support life.

    Astronomers estimate that there are 100 billion galaxies in the universe. If you want to extrapolate those numbers, that means there are around 50,000,000,000,000,000,000 (50 quintillion) potentially habitable planets in the universe.

    As Arthur C. Clarke, physicist and author of 2001: A Space Odyssey wrote, “The idea that we are the only intelligent creatures in a cosmos of a hundred billion galaxies is so preposterous that there are very few astronomers today who would take it seriously. It is safest to assume therefore, that they are out there and to consider the manner in which this may impinge upon human society.”To an objectivist, empirical view, the rules of Bayesian statistics can be justified by requirements of rationality and consistency and interpreted as an extension of logic. Using a subjectivist view, however, the state of knowledge measures a “personal belief”.

    More information: “Life might be rare despite its early emergence on Earth: a Bayesian analysis of the probability of abiogenesis” http://arxiv.org/abs/1107.3835 and physorg.com

    The Daily Galaxy via Princeton University

    Image credit: Image credit: NASA/ESA/IAC/HFF Team, STScI

    See the full article here .

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  • richardmitnick 11:15 pm on January 14, 2016 Permalink | Reply
    Tags: , , Exoplanets, ,   

    From Ethan Siegel: “Kepler found its longest-period exoplanet ever” 

    Starts with a bang
    Starts with a Bang

    Ethan Siegel

    Temp 1
    Image credit: NASA / Michele Johnson.

    And it didn’t even need a transit to do it!

    “Mars is much closer to the characteristics of Earth. It has a fall, winter, summer and spring. North Pole, South Pole, mountains and lots of ice. No one is going to live on Venus; no one is going to live on Jupiter.”
    -Buzz Aldrin

    The Kepler spacecraft was one of the most brilliant technical and scientific achievements of the 2010s.

    NASA Kepler Telescope

    By launching a telescope into space and pointing it at the same field-of-view of stars for years and years, collecting the light from each one continuously, it became sensitive to tiny, minuscule variations in the intensity of their starlight.

    Image credit: Painting by Jon Lomberg, Kepler mission diagram added by NASA.

    There are a number of reasons the amount of light a star emits could vary in intensity: it could be an intrinsically variable star (like a Cepheid, RR Lyrae or Delta Scuti variable, among others), it could be an eclipsing binary star system (an example of an extrinsic variable star), where one star periodically slips behind the other, or it could be due to the most exciting reason of all: something is transiting in front of that star to block a fraction of its light.

    Image credit: NASA Ames.

    Sometimes, the transiting object could be close by, like an asteroid or a Kuiper belt object.

    Known objects in the Kuiper belt beyond the orbit of Neptune. (Scale in AU; epoch as of January 2015.)

    Other times, it could be more distant, like an interstellar object. But what Kepler’s built to look for, and what it’s particularly seeking, is planets around the stars it’s looking at. In order for this method to be successful, you need for a number of things to happen all at once:

    You need the planetary orbit to be so serendipitously aligned with the star and your spacecraft that the orbital path appears to transit across the disk of the star from your point of view.

    You need the ratio of the planet’s size to the star’s to be large enough that your spacecraft can measure the transit’s magnitude.
    And you need the planet to transit across the star’s surface more than once so that you can be sure it wasn’t a foreground object having nothing to do with the star system you’re observing.

    Even if every star out there had a Solar System like our own, all three of these things being true would be a relatively rare occurrence, so if you’re just searching blindly, you need lots of targets. Kepler began operation in late 2009, pointing at an area of the Milky Way containing about 150,000 stars it was sensitive to. It measured the light from those stars over a long period of time — years — and to date has found close to 10,000 planetary candidates using these criteria. Some of them turn out not to be planets after all, as lots of things can mimic a planetary signal.

    This is why, if you want to confirm an exoplanet candidate, you need a second, independent method to do so.

    Image credit: ESO, under the Creative Commons Attribution 4.0 International License.

    Normally, we use the stellar wobble method. Every planet that orbits a star has a mass, and just as the star pulls the planet into an elliptical orbit around it, the planet adds a tiny elliptical motion to the star’s orbit as well. This doesn’t produce a perceptible change in the star’s position, but does produce a perceptible change in the wavelength of the light emitted from the star: a redshift or blueshift, as the star moves either away or towards you in its periodic dance.

    Over a thousand planetary systems discovered by Kepler have been confirmed by the stellar wobble method, including Kepler-56, which is a star that’s presently evolving into a red giant as its core runs out of hydrogen to burn. Two large, inner planets — one about the mass of Neptune and one about half the mass of Jupiter — were found around this system. The large masses and close-in orbits make these exactly the types of planets that Kepler can find most easily, and also the types of planets that can easily and quickly be confirmed via stellar wobble.

    Image credit: NASA Ames/W. Stenzel, of the Kepler planetary candidates as of July 2015.

    Kepler’s no good at finding planets that are much farther out than Earth is from our Sun, since in order to build up a robust, quality signal, you need multiple transits (more is better) of the planet across the star, which is very hard to do for a planet like say, Jupiter in our Solar System, which has an orbital period of 12 years, especially if your spacecraft has only been up there since 2009. To make things even worse, your chances of having a good alignment with a planet that’s more distant from its parent star drops very quickly as you move away. There’s a reason that hot, inner worlds are so abundant with Kepler: they’re the easiest ones to find.

    But sometimes, you do your follow-up for the transiting planets (the ones Kepler easily finds), and when you look for the stellar wobble, you not only find it…

    Image credit: D. Huber et al., Science 18 October 2013: Vol. 342 no. 6156 pp. 331–334; DOI: 10.1126/science.1242066.

    but you find something else. In the case of Kepler-56, the innermost planet (blue line) gives off a clear signal that can be teased out; the second large planet (red line, higher mass) gives off an even more prominent signal. Yet perhaps the most notable signal is just labeled “trend,” which you need to add to the two planetary signals to get the observed data. When this was first reported in 2013, it was assumed this was probably a planet, but more data was needed to know its orbital properties: mass and period. As first released this week at the American Astronomical Society’s annual meeting, Kepler-56 appears to have a third planet orbiting it — about six times the mass of Jupiter with a period of around three Earth-years — thanks to the work of Justin Otor, Benjamin Montet and John A. Johnson.

    Image credit: Danny Barringer, of Justin Otor’s poster at AAS 227.

    Finally, one almost complete “wobble cycle” of the outer planet has been observed with the follow-up data, and it’s actually a planet that doesn’t transit the star from our line-of-sight. It turns out that Kepler really can’t find these outer worlds on its own, but the clues that Kepler provides, of where to look for planetary systems where the stellar wobble can teach you so much more, can lead us to discover massive, outer planets that we never would’ve known to look for otherwise. Where there’s smoke, you look for the fire; where there are inner worlds, look for the outer ones. If you see the steep rise or fall associated with a massive wobble, you just might break the record.

    This article was partially based on information obtained during the 227th American Astronomical Society meeting, some of which may be unpublished.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

  • richardmitnick 3:53 pm on December 1, 2015 Permalink | Reply
    Tags: , , Exoplanets,   

    From Berkeley: “Exoplanet kicked into exile” 

    UC Berkeley

    UC Berkeley

    December 01, 2015
    Robert Sanders

    A planet discovered last year sitting at an unusually large distance from its star – 16 times farther than Pluto is from the sun – may have been kicked out of its birthplace close to the star in a process similar to what may have happened early in our own solar system’s history.

    A wide-angle view of the star HD 106906 taken by the Hubble Space Telescope and a close-up view from the Gemini Planet Imager reveal a dynamically disturbed system of comets, suggesting a link between this and the unusually distant planet (upper right), 11 times the mass of Jupiter. Click image for hi-res versions & caption. Paul Kalas image, UC Berkeley.

    Images from the Gemini Planet Imager (GPI) in the Chilean Andes and the Hubble Space Telescope show that the star has a lopsided comet belt indicative of a very disturbed solar system, and hinting that the planet interactions that roiled the comets closer to the star might have sent the exoplanet into exile as well.

    NASA Hubble Telescope
    NASA/ESA Hubble

    The planet may even have its own ring of debris that it dragged along with it.

    “We think that the planet itself could have captured material from the comet belt, and that the planet is surrounded by a large dust ring or dust shroud,” said Paul Kalas, an adjunct professor of astronomy at the University of California, Berkeley. “We conducted three tests and found tentative evidence for a dust cloud, but the jury is still out.”

    “The measurements we made on the planet suggest it may be dustier than comparison objects, and we are making follow-up observations to check if the planet is really encircled by a disk – an exciting possibility,” added Abhi Rajan, a graduate student at Arizona State University who analyzed the planet images.

    Such planets are of interest because in its youth, our own solar system may have had planets that were kicked out of the local neighborhood and are no longer among of the eight planets we see today.

    “Is this a picture of our solar system when it was 13 million years old?” asks Kalas. “We know that our own belt of comets, the Kuiper belt, lost a large fraction of its mass as it evolved, but we don’t have a time machine to go back and see how it was decimated.

    Known objects in the Kuiper belt beyond the orbit of Neptune. (Scale in AU; epoch as of January 2015.

    One of the ways, though, is to study these violent episodes of gravitational disturbance around other young stars that kick out many objects, including planets.”

    The disturbance could have been caused by a passing star that perturbed the inner planets, or a second massive planet in the system. The GPI team looked for another large planet closer to the star that may have interacted with the exoplanet, but found nothing outside of a Uranus-sized orbit.

    Kalas and Rajan will discuss the observations during a Google+ Hangout On Air at 7 a.m. Hawaii time (noon EST) on Dec. 1 during Extreme Solar Systems III, the third in a series of international meetings on exoplanets that this year takes place on the 20th anniversary of the discovery of the first exoplanet in 1995. Viewers without Google+ accounts may participate via YouTube.

    A paper about the results, with Kalas as lead author, was published in the The Astrophysical Journal on Nov. 20, 2015.

    Young, 13-million-year-old star

    The star, HD 106906, is located 300 light years away in the direction of the constellation Crux and is similar to the sun, but much younger: about 13 million years old, compared to our sun’s 4.5 billion years. Planets are thought to form early in a star’s history, however, and in 2014 a team led by Vanessa Bailey at the University of Arizona discovered a planet HD 106906 b around the star weighing a hefty 11 times Jupiter’s mass and located in the star’s distant suburbs, an astounding 650 AU from the star (one AU is the average distance between Earth and the sun, or 93 million miles).

    The star HD 106906 and the planet HD 106906 b, with Neptune’s orbit for comparison

    The Gemini Planet Imager mounted on the Gemini South telescope in Chile. Courtesy of Gemini Telescopes.

    Planets were not thought to form so far from their star and its surrounding protoplanetary disk, so some suggested that the planet formed much like a star, by condensing from its own swirling cloud of gas and dust. The GPI and Hubble discovery of a lopsided comet belt and possible ring around the planet points instead to a normal formation within the debris disk around the star, but a violent episode that forced it into a more distant orbit.

    Kalas and a multi-institutional team using GPI first targeted the star in search of other planets in May 2015 and discovered that it was surrounded by a ring of dusty material very close to the size of our own solar system’s Kuiper Belt. The emptiness of the central region – an area about 50 AU in radius, slightly larger than the region occupied by planets in our solar system – indicates that a planetary system has formed there, Kalas said.

    He immediately reanalyzed existing images of the star taken earlier by the Hubble Space Telescope and discovered that the ring of dusty material extended much farther away and was extremely lopsided. On the side facing the planet, the dusty material was vertically thin and spanned nearly the huge distance to the known planet, but on the opposite side the dusty material was vertically thick and truncated.

    “These discoveries suggest that the entire planetary system has been recently jostled by an unknown perturbation to its current asymmetric state,” he said. The planet is also unusual in that its orbit is possibly tilted 21 degrees away from the plane of the inner planetary system, whereas most planets typically lie close to a common plane.

    Kalas and collaborators hypothesized that the planet may have originated from a position closer to the comet belt, and may have captured dusty material that still orbits the planet. To test the hypothesis, they carefully analyzed the GPI and Hubble observations, revealing three properties about the planet consistent with a large dusty ring or shroud surrounding it. However, for each of the three properties, alternate explanations are possible.

    The investigators will be pursuing more sensitive observations with the Hubble Space Telescope to determine if HD 106906b is in fact one of the first exoplanets that resembles Saturn and its ring system.

    The inner belt of dust around the star has been confirmed by an independent team using the planet-finding instrument SPHERE on the ESO’s Very Large Telescope in Chile. The lopsided nature of the debris disk was not evident, however, until Kalas called up archival images from Hubble’s Advanced Camera for Surveys.

    The GPI Exoplanet Survey, operated by a team of astronomers at UC Berkeley and 23 other institutions, is targeting 600 young stars, all less than approximately 100 million years old, to understand how planetary systems evolve over time and what planetary dynamics could shape the final arrangement of planets like we see in our solar system today. GPI operates on the Gemini South telescope and provides extremely high-resolution, high-contrast direct imaging, integral field spectroscopy and polarimetry of exoplanets.

    Gemini South telescope
    Gemini South

    Among Kalas’s coauthors are UC Berkeley graduate student Jason Wang. The research was supported by the National Science Foundation and NASA’s Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA’s Science Mission Directorate.

    NASA NExSS bloc

    See the full article here .

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  • richardmitnick 8:49 am on November 28, 2015 Permalink | Reply
    Tags: , , Exoplanets,   

    From Hawaii Blog via UH: “Astronomers to Explore ‘Extreme Solar Systems’” 

    U Hawaii

    University of Hawaii

    Institute for Astronomy

    U Hawaii Institute for Astonomy Mauna Kea
    IFA at Manua Kea

    Hawaii Blog bloc
    Hawaii Blog


    As solar systems go, the one we live in is pretty boring. In the Hitchhiker’s Guide by the great Douglas Adams, our neighborhood was described as being “far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the galaxy.” (Our planet was deemed “mostly harmless.”)

    But planets and stars can be found in some pretty remarkable configurations. And beginning this weekend, an international conference dedicated to “Extreme Solar Systems” will be held on Hawaii Island, with a complementary public talk scheduled for next Wednesday in Honolulu.

    What constitutes an “extreme” solar system? One with two stars, perhaps?

    “For those who are interested in science fiction, they might remember Luke Skywalker coming out of his den and walking toward the horizon and seeing two suns,” said Nader Haghighipour, a researcher at the University of Hawaii at Manoa Institute for Astronomy, on tonight’s Bytemarks Cafe. “Well, that was science fiction many years ago, but a small group of us have been promoting the idea that science fiction is not entirely fiction and that there’s actually science behind it.”

    Haghighipour had been adamant for more than 20 years that circumbinary solar systems existed, but it wasn’t until observing instruments and scientific advances made it possible to find one. And the launch of the Kepler space observatory in 2009 was a major turning point.

    NASA Kepler Telescope

    Kepler scientists started discovering new exoplanets right out of the gate, and to date the space telescope has helped find over 1,000 exoplanets in about 440 star systems (with another 3,100 candidates waiting to be confirmed).

    Haghighipour was poring over the Kepler data as well.

    “We saw something very interesting about one specific binary star system: we saw that when the two stars go around each other, the light of each one of them dims for a very short amount of time and a very short amount of intensity,” he recalled. “Being promoters of planets with more than one sun, that was the first thing that occurred to us, that it may be a planet that was blocking the light coming from each one of the stars.”

    Still, astronomy is a field that demands lots of study and independent confirmation before declaring any discovery.

    “Three years, four years of data coming from Kepler helped us to get that model more and more solid, and eventually we could make predictions of when would be the next time the planet will go around those stars,” Haghighipour said. “When we discovered that, that was the proof.”

    The news made global headlines. Since then, he’s helped discover ten more planets that orbit two stars.


    Haghighipour explained how a circumbinary system would look.

    “In the context of our solar system, think of Mercury being another sun, and Jupiter and Earth going around both of them at the same time,” he said. “You wake up in the morning, you have two suns out there, you have two shadows when you walk, and just imagine one of the suns sets, the other stays up, or they both go down.”

    Of course, to see a two-sun sunset, the solar system needs to have planets that can support life. And with so many exoplanets now catalogued by astronomers, it was inevitable that some would be found in the Goldilocks Zone around their stars — an orbit not too cold and not too hot for life to exist.

    “So far we have discovered ten of them, and we are going to announce two new ones next week,” Haghighipour teased. “And among these ten, three of them are right in the habitable zone: they’re large, they’re as big as Jupiter, so they themselves cannot be habitable, but similar to our Jupiter, they may have moons that are big enough to be habitable.”


    The “Extreme Solar Systems” conference is only the third such international gathering, following meetings in Greece in 2007 and Wyoming in 2011. But the Hawaii meeting marks the 20th anniversary of the discovery of the first extra-solar planets. More than 300 “hardcore astronomers” will spend a week at the Waikoloa Marriott exploring hundreds of poster presentations, dozens of scientific sessions, and many talks.

    Fortunately, Honolulu residents will also have a chance to soak up stories about unusual star systems. On Wednesday, Dec. 2, the UH Institute for Astronomy is hosting a “Frontiers of Astronomy” public talk at the UH Manoa Art Auditorium. Titled simply “Exoplanets,” the event will feature four planet hunters who are also presenting at the Big Island conference: Haghighipour, Andrew Howard, Paul Kalas from Berkeley and Josh Winn from MIT.

    Each researcher represents a different area of solar system research, and each will give a 10 minute talk. Then the floor will be opened to audience questions. The event is free and open to the public and starts at 7:30 p.m.

    For more information on the “Extreme Solar Systems” conference, visit the official website. For more information on the public talk on Wednesday, visit ifa.hawaii.edu. You can also follow @UHIfA on Twitter or connect with the institute on Facebook.

    See the full article here .

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  • richardmitnick 9:43 am on November 26, 2015 Permalink | Reply
    Tags: , , Exoplanets, LCOGT   

    From LCOGT: “A blue, neptune-size exoplanet around a red dwarf star” 

    LCOGT bloc

    Las Cumbres Observatory Global Telescope Network

    Edward Gomez

    A team of astronomers have used the LCOGT network to detect light scattered by tiny particles (called Rayleigh scattering), through the atmosphere of a Neptune-size transiting exoplanet. This suggests a blue sky on this world which is only 100 light years away from us. The result was published in the Astrophysical Journal on November 20 (and is available on ArXiV).

    Transits occur when an exoplanet passes in front of its parent star, reducing the amount of light we receive from the star by a small fraction. When the orbit of an exoplanet is aligned just right for transits to occur, astronomers can measure the planet’s size at different wavelengths in order to generate a spectrum of its atmosphere. The spectrum then reveals the substances present in the planet’s atmosphere, and therefore its composition. This measurement is most often performed using infrared light, where the planet is brightest and most easily observed. During the last few years, researchers have been probing the atmospheres of several small exoplanets with large ground and space-based telescopes, but have found it challenging to determine their composition using this method. This is either because the planets have clouds (which obscure the atmosphere) or because the measurements were not sufficiently precise.

    Image credit: NAOJ, artists impression of GJ 3470b and its host star.

    At four times the size of the Earth, GJ 3470b is a transiting exoplanet closer in size to our own planet than to the hot Jupiters (about 10 times the size of the Earth) which so far make up the majority of exoplanets with well-characterized atmospheres. Astronomers led by Diana Dragomir of the University of Chicago have followed up on a discovery by a different group, whose results tentatively hinted at the presence of Rayleigh scattering in the atmosphere of GJ 3470b. Dr. Dragomir’s team acquired and combined transit observations from all of LCOGT’s observatory sites (Hawaii, Texas, Chile, Australia and South Africa) to conclusively confirm the detection of Rayleigh scattering for GJ 3470b.

    The result is significant for several reasons. GJ 3470b is the smallest exoplanet for which a detection of Rayleigh scattering exists. While this planet is also believed to be cloudy or hazy, the measurement tells astronomers that the planet has a thick hydrogen-rich atmosphere below a layer of haze which scatters blue light. Indeed, the sky is blue on GJ 3470b. Moreover, the planet orbits a small (red dwarf) star, which means it blocks a large amount of light during every transit, making the transit easier to detect and the planet more easily characterisable. Finally, this measurement is the first clear detection of a spectroscopic feature in the atmosphere of an exoplanet that was made only with small (1.0m and 2.0m) telescopes. The team has also supplemented the LCOGT data with observations obtained from the 1.5m Kuiper Telescope in Arizona.

    LCOGT Steward Observatory 61 inch Kuiper Telescope
    LCOGT Steward Observatory 61 inch Kuiper Telescope interior
    LCOGT Steward 1.5 meter telescope in Arizona

    Dr. Dragomir, who carried out the project while she was a researcher at LCOGT, says that “this detection brings us closer to understanding the nature of increasingly smaller exoplanets through the use of a novel approach which allows us to probe the atmospheres of exoplanets even if they are cloudy.” At the same time, the result highlights the role that meter-size telescopes can play toward characterising the atmospheres of these worlds.

    See the full article here.

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    LCOGT Las Cumbres Observatory Global Telescope Network
    Sutherland is home to several telescopes including the 11-meter SALT.

    Las Cumbres Observatory Global Telescope Network is an integrated set of robotic telescopes, distributed around the world. The network currently includes two 2-meter telescopes, sited in Hawaii and eastern Australia, nine 1-meter telescopes, sited in Chile, South Africa, eastern Australia, and Texas, and three 0.4-meter telescopes, sited in Chile and the Canary Islands.

    LCOGT map

  • richardmitnick 7:49 pm on November 16, 2015 Permalink | Reply
    Tags: , , Exoplanets,   

    From SPACE.com: “Exoplanet’s Global Winds Let Rip at 5,400 MPH” 

    space-dot-com logo


    November 16, 2015
    Irene Klotz

    A windy day on HD 189733b is nothing to take lightly. Credit: Mark A. Garlick/University of Warwick

    The planet, located about 63 light years away in the constellation Vulpecula, has winds reaching 5,400 mph, roughly 20 times faster than anything ever experienced on Earth.

    Granted, everything about HD 189733b is extreme. It’s about 10 percent bigger than Jupiter, but its located 180 times closer to its parent star than Jupiter is to the sun, far closer than even Mercury, the innermost planet in the solar system.

    Scientists estimate its temperature reaches almost 3,700 degrees Fahrenheit.

    HD 189733b orbits its host start every 2.2 days, at a breakneck speed of 341,000 mph.

    Scientists at the University of Warwick were able to measure velocities on the day and night sides of the planet. They discovered the 5,400 mph wind blowing from the day to the night side.

    “As parts of HD 189733b’s atmosphere move towards or away from the Earth the Doppler effect changes the wavelength of this feature, which allows the velocity to be measured,” lead researcher Tom Louden said in a statement. “This is the first ever weather map from outside of our solar system.”

    Astronomers used HARPS, the High Accuracy Radial velocity Planet Searcher, in La Silla, Chile, to watch the planet as it passed in front of its host star, relative to the telescope’s line of sight.

    ANALYSIS: Exoplanet Weather Forecast: Hot and Nasty

    “The surface of the star is brighter at the center than it is at the edge, so as the planet moves in front of the star the relative amount of light blocked by different parts of the atmosphere changes. For the first time we’ve used this information to measure the velocities on opposite sides of the planet independently, which gives us our velocity map,” Louden said.

    The research is being published in the Astrophysical Journal Letters.

    See the full article here .

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  • richardmitnick 2:46 pm on October 6, 2015 Permalink | Reply
    Tags: , , Exoplanets, ,   

    From U Washington: “Where to look for life? UW astronomers devise ‘habitability index’ to guide future search” 

    U Washington

    University of Washington

    October 5, 2015
    Peter Kelley

    The James Webb Space Telescope, a large infrared telescope with a 6.5-meter primary mirror, is scheduled to be launched on an Ariane 5 rocket from French Guiana in October of 2018 and will be the premier NASA observatory of the next decade, serving thousands of astronomers around the world. UW astronomers have created a “habitability index for transiting planets” to help guide the ongoing search for life beyond Earth. NASA

    Powerful telescopes are coming soon. Where exactly shall we point them?

    Astronomers with the University of Washington’s Virtual Planetary Laboratory have created a way to compare and rank exoplanets to help prioritize which of the thousands discovered warrant close inspection in the search for life beyond Earth.

    The new metric, called the Habitability index for transiting planets, is introduced in a paper accepted for publication in the Astrophysical Journal by UW astronomy professors Rory Barnes and Victoria Meadows, with research assistant and co-author Nicole Evans.

    “Basically, we’ve devised a way to take all the observational data that are available and develop a prioritization scheme,” said Barnes, “so that as we move into a time when there are hundreds of targets available, we might be able to say, ‘OK, that’s the one we want to start with.’”

    The Kepler Space Telescope has enabled astronomers to detect thousands of exoplanets, those beyond our solar system — far more than can be investigated one by one.

    NASA Kepler Telescope

    The James Webb Space Telescope, set for launch in 2018, will be the first able to actually measure the atmospheric composition of a rocky, possibly Earthlike planet far off in space, and so vastly enhance the search for life.

    Astronomers detect some planets when the worlds transit or pass in front of their host star, thus blocking some of the light. The Transiting Exoplanet Survey Satellite, or TESS, is scheduled to launch in 2017 and will find many more worlds in this way.


    But it’s the Webb telescope and its “transit transmission spectroscopy” that will really be able to study planets closely to hunt for life.

    But access to such telescopes is expensive and the work is methodical and time-consuming. The Virtual Planetary Laboratory’s index is a tool to help fellow astronomers decide which worlds might have the better chance of hosting life, and so are worthy of focusing limited resources on.

    Traditionally, astronomers have focused the search by looking for planets in their star’s habitable zone”— more informally called the “Goldilocks zone” — which is the swath of space that’s “just right” to allow an orbiting Earth-like planet to have liquid water on its surface, perhaps giving life a chance. But so far that has been just a sort of binary designation, indicating only whether a planet is, or is not, within that area considered right for life.

    “That was a great first step, but it doesn’t make any distinctions within the habitable zone,” Barnes said. “Now it’s as if Goldilocks has hundreds of bowls of porridge to choose from.”

    The new index is more nuanced, producing a continuum of values that astronomers can punch into a Virtual Planetary Laboratory Web form to arrive at the single-number habitability index, representing the probability that a planet can maintain liquid water at its surface.

    In creating the index, the researchers factored in estimates of a planet’s rockiness, rocky planets being the more Earth-like. They also accounted for a phenomenon called eccentricity-albedo degeneracy, which comments on a sort of balancing act between the a planet’s albedo — the energy reflected back to space from its surface — and the circularity of its orbit, which affects how much energy it receives from its host star.

    The two counteract each other. The higher a planet’s albedo, the more light and energy are reflected off to space, leaving less at the surface to warm the world and aid possible life. But the more noncircular or eccentric a planet’s orbit, the more intense is the energy it gets when passing close to its star in its elliptic journey.

    A life-friendly energy equilibrium for a planet near the inner edge of the habitable zone — in danger of being too hot for life — Barnes said, would be a higher albedo, to cool the world by reflecting some of that heat into space. Conversely, a planet near the cool outer edge of the habitable zone would perhaps need a higher level of orbital eccentricity to provide the energy needed for life.

    Barnes, Meadows and Evans ranked in this way planets so far found by the Kepler Space Telescope, in its original mission as well as its K2 follow-up mission. They found that the best candidates for habitability and life are those planets that get about 60 percent to 90 percent of the solar radiation that the Earth receives from the sun, which is in keeping with current thinking about a star’s habitable zone.

    The research is part of the ongoing work of the Virtual Planetary Laboratory to study faraway planets in the ongoing search for life, and was funded by the NASA Astrobiology Institute.

    “This innovative step allows us to move beyond the two-dimensional habitable zone concept to generate a flexible framework for prioritization that can include multiple observable characteristics and factors that affect planetary habitability,” said Meadows.

    “The power of the habitability index will grow as we learn more about exoplanets from both observations and theory.”

    See the full article here .

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    So what defines us — the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

  • richardmitnick 1:43 pm on September 19, 2015 Permalink | Reply
    Tags: , , CNET, , Exoplanets   

    From CNET via Dunlap: “Watch an exoplanet orbit a distant star” 



    U Toronto Dunlap bloc

    18 September 2015
    Michelle Starr

    Exoplanets, or planets outside the solar system, are notoriously difficult to see. We know they exist, but these planets are not usually seen directly.

    Planets only reflect the light of the stars, and stars are so bright that the any light reflected off the planet is very faint in comparison. Typically, stars are a million times brighter than their orbiting planets.

    The presence of exoplanets is extrapolated by observing the star it orbits. When the star’s light dims, astronomers are able to determine that a planet is passing in front of it and blocking some of the light from reaching Earth. At time of writing, NASA’s exoplanet archive lists 1,890 confirmed exoplanets located by the Kepler mission.

    NASA Kepler Telescope

    Using the Chile-based Gemini South telescope’s Gemini Planet Imager (GPI) instrument, a team of researchers led by PhD candidate Maxwell Millar-Blanchaer was able to take a series of images of a planet in orbit around a star named Beta Pictorus, which lies approximately 63 light-years from Earth in the direction of the constellation of Pictor.

    Gemini South telescope
    Gemini South Interior
    NOAO/Gemini South

    Gemini Planet Imager
    GPI on Gemini South

    The planet’s name is Beta Pictoris b, discovered in 2008, and it’s a gas giant. The system of Beta Pictorus is a complex one. It contains a massive debris disk, an orbiting gas clouds and comets.

    Beta Pictorus

    This composite image represents the close environment of Beta Pictoris as seen in near infrared light. This very faint environment is revealed after a very careful subtraction of the much brighter stellar halo. The outer part of the image shows the reflected light on the dust disc, as observed in 1996 with the ADONIS instrument on ESO’s 3.6 m telescope; the inner part is the innermost part of the system, as seen at 3.6 microns with NACO on the Very Large Telescope. The newly detected source is more than 1000 times fainter than Beta Pictoris, aligned with the disc, at a projected distance of 8 times the Earth-Sun distance. Both parts of the image were obtained on ESO telescopes equipped with adaptive optics.


    ESO 3.6m telescope & HARPS at LaSilla
    ESO 3.6 meter telescope interior
    ESO 3.6m telescope at LaSilla


    ESO VLT Interferometer

    Beta Pictorus b, with a radius 65 percent larger than Jupiter’s, is a relatively young planet, orbiting a very young star only somewhere between 8 million and 20 million years old. Beta Pictorus b interacts gravitationally with the debris disk, within which, scientists theorise, planetary formation may still be ongoing. This makes the Beta Pictorus system and planet Beta Pictorus b excellent for studying planetary formation theories.

    The planet was imaged from November 2013 to April 2015, capturing 1.5 years of its 22-year orbital period. The Gemini Planet Imager occludes the light from Beta Pictorus, allowing the camera to capture direct images of the planet, resulting in some of the best photos of Beta Pictorus b yet.

    “The images in the series represent the most accurate measurements of the planet’s position ever made,” Millar-Blanchaer said. “In addition, with GPI, we’re able to see both the disk and the planet at the exact same time. With our combined knowledge of the disk and the planet, we’re really able to get a sense of the planetary system’s architecture and how everything interacts.”

    The team’s paper, published this week in The Astrophysical Journal, also refines orbital measurements of the star and the debris disk, clarifying their relationship. It also refines the mass of the star Beta Pictorus, which comes in at around 1.6 solar masses, and demonstrates that Beta Pictorus b is unlikely ever to pass directly between Beta Pictorus and Earth.

    “It’s remarkable that Gemini is not only able to directly image exoplanets but is also capable of effectively making movies of them orbiting their parent star,” said Chris Davis, astronomy division program director at the National Science Foundation, which helps fund the Gemini telescopes.

    “The disk of gas and dust from which planets are currently forming was one of the first to be observed and is a fabulous laboratory for the study of young solar systems.”

    See the full article here .

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