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  • richardmitnick 12:02 pm on October 21, 2016 Permalink | Reply
    Tags: , , Exoplanets, Hot Jupiter clouds,   

    From Many Worlds- “Exoplanet Clouds: Friend and Foe” 

    NASA NExSS bloc

    NASA NExSS

    Many Worlds

    Many Words icon

    2016-10-21
    Marc Kaufman

    1
    An illustration representing how hot Jupiters of different temperatures and different cloud compositions might appear to a person flying over the day side of these planets on a spaceship, based on computer modeling. (NASA/JPL-Caltech/University of Arizona/V. Parmentier)

    Understanding the make-up and dynamics of atmospheric clouds is crucial to our interpretations of how weather and climate behave on Earth, and so it should come as no surprise that clouds are similarly essential to learning the nature and behavior of exoplanets.

    On many exoplanets, thick clouds and related, though different, hazes have been impediments to learning what lies in the atmospheres and on surfaces below. Current technologies simply can’t pierce many of these coverings, and scientists have struggled to find new approaches to the problem.

    One class of exoplanets that has been a focus of cloud studies has been, perhaps unexpectedly, hot Jupiters — those massive and initially most surprising gas balls that orbit very close to their suns.

    Because of their size and locations, the first exoplanets detected were hot Jupiters. But later work by astronomers, and especially the Kepler Space Telescope, has established that they are not especially common in the cosmos.

    Due to their locations close to suns, however, they have been useful targets of study as the exoplanet community moves from largely detecting new objects to trying to characterize them, to understanding their basic features. And clouds are a pathway to that characterization.

    For some time now, scientists have understood that the night sides of the tidally-locked hot Jupiters generally do have clouds, as do the transition zones between day and night. But more recently, some clouds on the super-hot day sides — where temperatures can reach 2400 degrees Fahrenheit –have been identified as well.

    Vivien Parmentier, a Sagan Fellow at the University of Arizona, Tucson, as well as planetary scientist Jonathan Fortney of the University of California at Santa Cruz have been studying those day side hot Jupiter clouds to see what they might be made of, and how and why they behave as they do.

    “Cloud composition changes with planet temperature,” said Parmentier, who used a 3D General Circulation Model (GCM) to track where clouds form in hot Jupiter atmospheres, and what impact they have on the light emitted and reflected by the planets. “The offsetting light curves tell the tale of cloud composition. It’s super interesting, because cloud composition is very hard to get otherwise.”

    The paper by Parmentier, Fortney and others was published in The Astrophysical Journal.

    2
    Artist’s impression of a hot Jupiter. (NASA)

    Solid observational evidence of clouds on the days sides of hot Jupiters has been collected for only a short time, and is done by measuring parent starlight being reflected off the atmosphere. Enough information has accumulated by now, Fortney said, to begin to offer theoretical explanations of the measurements being made.

    “What this suggests is that the cloud behavior is quite complex — there is no ‘uniform planet-wide cloud,’ for these tidally locked planets,” he said in an email.

    “The hot day side may sometimes lack clouds, compared to the cooler night side, where many clouds form. Energy redistribution, via winds, leads to gas that is moving into “sunset” from day to night being cloud-free, but gas going into “sunrise,” moving from night to day is full our cloud material that will evaporate when the gas warms up.

    The atmospheres are way too hot for water clouds. Instead, the cloud material detected has been iron and silicate rocks (well-known from brown dwarf atmospheres), and manganese sulfide (which has been suggested for brown dwarf as well.)

    The different elements and compounds in the clouds give hints about the appearance of the planets, and Parmentier used the GCM model to predict what these planets would look like to the human eye.

    The differences in color, said Fortney, are a function of the amount of heat coming off the planet and the stellar scattered light coming off of atmospheric gases and clouds. “Not all clouds are the same color, which is fun.”

    He also said that “this is the first in what will be a longer study to better understand the transport of cloud material around the planets.

    For this first study, we only suggest that clouds will form when the temperature is right, but we didn’t track how the cloud material moves with the flow. That is the next step for a more comprehensive and accurate model.”

    3
    Hot Jupiters often have cloud or haze layers in their atmospheres. This may prevent space telescopes from detecting atmospheric water that lies beneath the clouds, according to an earlier study in the Astrophysical Journal. (NASA/JPL-Caltech)

    he new insights into hot Jupiter clouds via the GCM allowed the team to draw conclusions about wind and temperature differences.

    Just before the hotter planets passed behind their stars, a blip in the planet’s optical light curve revealed a “hot spot” on the planet’s eastern side. And on cooler eclipsing planets, a blip was seen just after the planet re-emerged on the other side of the star, this time on the planet’s western side.

    The early blip on hotter worlds was interpreted as being powerful winds that were pushing the hottest, cloud-free part of the day side atmosphere to the east. Meanwhile, on cooler worlds, clouds could bunch up and reflect more light on the “colder,” western side of the planet, causing the post-eclipse blip.

    “We’re claiming that the west side of the planet’s day side is more cloudy than the east side,” Parmentier said in a JPL release.

    While the puzzling pattern has been seen before, this research was the first to study all the hot Jupiters showing this behavior.

    This led to another first. By teasing out out how clouds are distributed, which is intimately tied to the planet’s overall temperature, scientists were able to determine the compositions of the clouds — likely formed as exotic vapors condense to form minerals, chemical compounds like aluminum oxide, or even metals, like iron.

    The science team found that manganese sulfide clouds probably dominate on “cooler” hot Jupiters, while silicate clouds prevail at higher temperatures. On these planets, the silicates likely “rain out” into the planet’s interior, vanishing from the observable atmosphere.

    So while exoplanet clouds can and do mask important information about what lies below in a planet’s atmosphere, scientists are learning ways to use the information that clouds provide to push forward on that process of characterizing the vast menagerie of exoplanets being found.

    4
    Analysis of data from the Kepler space telescope has shown that roughly half of the dayside of the exoplanet Kepler-7b is covered by a large cloud mass. Statistical comparison of more than 1,000 atmospheric models show that these clouds are most likely made of enstatite, a common Earth mineral that is in vapor form at the extreme temperature on Kepler-7b. These models varied the altitude, condensation, particle size, and chemical composition of the clouds to find the right reflectivity and color properties to match the observed signal from the exoplanet. (NASA, edited by Jose-Luis Olivares/MIT)

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

     
  • richardmitnick 4:38 pm on August 1, 2016 Permalink | Reply
    Tags: , , Exoplanets, Habitability Index, , Virtual Planetary Laboratory   

    From Many Worlds: “Ranking Exoplanet Habitability” The Lost Post 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2016-03-23 [Finally!!]
    Marc Kaufman

    1
    The Virtual Planetary Lab at the University of Washington has been working to rank exoplanets (or exoplanet candidates) by how likely they are to be habitable. (Rory Barnes)

    Now that we know that there are billions and billions of planets beyond our solar system, and we even know where thousands of confirmed and candidate planets are located, where should we be looking for those planets that could in theory support extraterrestrial life, and might just possibly support it now?

    The first order answer is, of course, the habitable zone — that region around a host star that would allow orbiting planets to have liquid water on the surface at least some of the time.

    That assertion is by definition a theoretical one — at this point we have no detection of an exoplanet with liquid water orbiting a distant star — and it is actually a rather long-held view.

    For instance, this is what William Whewell, the prominent British natural philosopher-scientist-theologian (and Master of Trinity College at Cambridge) wrote in 1853:

    “The Earth is really the domestic hearth of this solar system; adjusted between the hot and fiery haze on one side, the cold and watery vapour on the other. This region is fit to be the seat of habitation; and in this region is placed the largest solid globe of our system; and on this globe, by a series of creative operations…has been established, in succession, plants, and animals, and man…The Earth alone has become a World.”

    Whewell wrongly limited his analysis to our solar system, but he was pretty much on target regarding the crude basics of a habitable zone. His was followed over the decades by other related theoretical assessments, including in more modern times Steven Dole for the Rand Corporation in 1964 and NASA’s Michael Hart in 1979. All pretty much based on an Earth-centric view of habitable zones throughout the cosmos.

    It was this approach, even in its far more sophisticated modern versions, that got some of the scientists at the University of Washington’s Virtual Planetary Laboratory thinking three years ago about how they might do better. What they wanted to do was to join the theory of the habitable (or more colloquially, the “Goldilocks zone”) with actual data now coming in from measurements of transiting exoplanets.

    Although the measurements remain pretty limited, the group was convinced that the process could come up with the beginnings of a “Habitability Index” that would rate — based on evidence-based calculations and models — which exoplanets had the best chance of being able to support life.

    “We certainly are constrained by the observations being made, but we do have some important physical measurements to work with,” said Rory Barnes, a astrophysical theorist with the VPL. “And what we’ve done is to connect the possibility of life with the fundamental observables we do have….This really hasn’t been done before.”

    2
    Of the 1,030 confirmed planets from Kepler, a dozen are less than twice the size of Earth and reside in the habitable zone of their host star. They are arranged by by size and by the type of star they orbit — from the M stars that are significantly cooler and smaller than the sun, to the K stars that are somewhat cooler and smaller than the sun, to the G stars that include the sun. The sizes of the planets are enlarged by 25 times compared to the stars. The Earth is shown for reference. (NASA Ames/JPL-CalTech/R. Hurt)

    The result was a detailed paper in the Astrophysical Journal that showed observations and modeling that can be harnessed together to come up with a list of the 10 exo-objects most likely to support life. I specifically didn’t write “exoplanets” because nine of the ten remain “candidate” planets detected by the Kepler Space Telescope as transiting objects that block out a small bit of light from the host star. But they have not yet been confirmed through other detection techniques.

    And why do the hard work of teasing out the potentially most habitable planets (objects) from the many thousands of others identified? Clearly, it’s not because the data will point to some planet/objects that have a very good chance of being habitable. The information available just won’t allow for that.

    Rather, the next-generation James Webb Space Telescope is scheduled to launch in 2018, and it will be able to measure the components of exoplanets and their atmospheres in a whole new way.But access to a telescope like the JWST is costly and the observing and analyzing is and time-consuming. And so the Virtual Planetary Laboratory’s index is designed to help fellow astronomers identify which worlds might have the best chance of hosting life, and so are worthy of all the necessary time and money.

    Is the Habitability Index that much more useful than the more traditional habitable zone assessments based on a planet’s proximity to a particular star of a particular strength? And is it more predictive than some related assessments such as the Earth Similarity Index, created by Abel Mendez at the University of Puerto Rico at Arecibo.

    Because it takes into account so much more information, it certainly seems likely that it is more predictive, especially as new and better information is added to the system. While the traditional habitable zone points to a locations, the Habitability Index identifies distinctions within a habitable zone that would make an exoplanet more or less likely to support life.

    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.

    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 non-circular 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.

    These are the kinds of measurements being analyzed as well by the NASA’s Kepler Habitable Zone Working Group, a collection of scientists within the Kepler team with the task of identifying some of the most promising targets for future observation.

    Stephen Kane is leading the group, and expects to come out with an assessment this summer.

    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 .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

     
  • richardmitnick 5:30 am on July 28, 2016 Permalink | Reply
    Tags: Biosignatures, Exoplanets, , ,   

    From Many Worlds: “Coming to Terms With Biosignatures” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2016-07-27
    Marc Kaufman
    marc.kaufman@manyworlds.space

    1
    Exoplanets are much too far away for missions to visit and explore, so scientists are learning about them remotely. That includes the question of whether they might support life — an aspect of exoplanet science that is getting new attention. This is artist Ron Miller’s impression of an exoplanet.

    The search for life beyond our solar system has focused largely on the detection of an ever-increasing number of exoplanets, determinations of whether the planets are in a habitable zone, and what the atmospheres of those planets might look like. It is a sign of how far the field has progressed that scientists are now turning with renewed energy to the question of what might, and what might not, constitute a sign that a planet actually harbors life.

    The field of “remote biosignatures” is still in its early stages, but a NASA-sponsored workshop underway in Seattle has brought together dozens of researchers from diverse fields to dig aggressively into the science and ultimately convey its conclusions back to the exoplanet community and then to the agency.

    While a similar NASA-sponsored biosignatures workshop put together a report in 2002, much has changed since then in terms of understanding the substantial complexities and possibilities of the endeavor. There is also a new sense of urgency based on the observing capabilities of some of the space and ground telescopes scheduled to begin operations in the next decade, and the related need to know with greater specificity what to look for.

    “The astrobiology community has been thinking a lot more about what it means to be a biosignature,” said Shawn Domogal-Goldman of the Goddard Space Flight Center, one of the conveners of the meeting. Some of the reason why is to give advice to those scientists and engineers putting together space telescope missions, but some is the pressing need to maintain scientific rigor for the good of one of humankind’s greatest challenges.

    “We don’t want to spend 20 years of our lives and billions in taxpayer money working for a mission to find evidence of life, and learn too late that our colleagues don’t accept our conclusions,” he told me. “So we’re bringing them all together now so we can all learn from each other about what would be, and what would not be, a real biosignature.”

    2
    How to measure the chemical signatures in the atmosphere of a transiting exoplanet. The total light measured off-transit (B in the lower left figure) decreases during the transit, when only the light from the star is measured (A). By subtracting A from B, we get the planet counterpart, and from this the “chemical fingerprints” of the planet atmosphere can be revealed. ( NASA/JPL-Caltech)

    The 3-day workshop is bringing together some 50 scientists ranging from astronomers, astrobiologists and planetary scientists to microbiologists and specialists in photosynthesis. Organized by NASA’s Nexus for Exoplanet System Science (NExSS) — an initiative created to encourage interdisciplinary collaboration — it has been tasked with putting together a report for the larger exoplanet community and ultimately for NASA.

    The first day of the workshop featured a review of previous work on biosignatures, which initially put forward the presence of oxygen in an exoplanet atmosphere as a strong and almost certain sign that biology was at work below. This is because oxygen, which is a byproduct of much life, bonds quickly with other molecules and so would be undetectable unless it was continuously replenished.

    But as outlined by Victoria Meadows, director of the Virtual Planet Laboratory at the University of Washington, more recent research has shown large amounts of oxygen can be produced without biology under a number of (usually extreme) conditions. There has been a resulting focus on potential false positive signals regarding oxygen and other molecules.

    From another perspective, Tim Lyons, a biogeochemist from the University of California, Riverside, used the early and middle Earth as an example how easy it is to arrive at a false negative result.

    He said that current thinking is that for as long as two billion years, Earth was inhabited but the lifeforms produced little oxygen. If analyzed from afar for all those years, the result would be a complete misreading of life on Earth.

    With these kinds of false positives and negatives in mind, Meadows said that the current approach to understanding biosignatures is to look beyond a single molecule to the broader planetary and solar environment.

    “We have to look not just at single biosignatures, but at their their context on the planet. How might life have modified an environment in a potentially detectable way? And having stepped back a bit, does the biosignature make sense?”

    As one example, while oxygen alone is no longer considered a sure biosignature, oxygen in an atmosphere in the presence of methane would be convincing because of the known results of the chemical interactions of the two.

    3
    Schematic for the concept of considering all small molecules in the search for biosignature gases.
    The goal is to start with chemistry and generate a list of all small molecules and filter them for the set that is stable and volatile in temperature and pressure conditions relevant for exoEarth planetary atmospheres. In the ideal situation, this overall conceptual process would lead to a finite but comprehensive list of molecules that could be considered in the search for exoplanet biosignature gases. (S. Seager and D. Beckner)

    In part because of the false positive/false negative issues involving oxygen, some have begun a concerted effort to produce a list of additional possible biosignatures. William Bains, a member of Sara Seager’s team at the Massachusetts Institute of Technology, described the blunderbuss approach they have adopted: examining some 14,000 compounds simple (fewer than six non-hydrogen atoms) and stable enough to exist in the atmosphere of an exoplanet.

    In their Astrobiology Journal article, Seager, Bains and colleagues wrote that “To maximize our chances of recognizing biosignature gases, we promote the concept that all stable and potentially volatile molecules should initially be considered as viable biosignature gases.”

    Elaborating during the workshop, Bains asked: “Why does life produce the gases that it does? We really don’t know, so we’re bringing in everything as a possibility.” Not surprisingly, he said, “The more you search, the more you find.”

    And as for the possibility of life existing in extreme environments, Bains referred to the microbes known to live in radioactive environments, in plastic, and virtually everywhere else on Earth.

    Because the science of remote biosignatures is still in its early stages, the unknowns can seem to overwhelm the knowns, making the whole endeavor seem near impossible. After all, it’s proven extremely difficult to determine whether there was ever life on “nearby” Mars, and scientists have Martian meteorites to study and rovers sending back information about the geology, the geochemistry, the weather, the atmospheric conditions and the composition of the planet.

    By comparison, learning how to probe the atmospheres of faraway exoplanets and assess what might or might not be a biosignature will have to be done entirely with next generation space telescopes and the massive ground telescopes in development. The information in the photons they collect will tell scientists what compounds are present, whether liquid water is present on the surface, and potentially whether the surface is changing with seasons. And then the interpretation begins.

    That’s why Mary Voytek, the originator of NExSS and the head of the NASA astrobiology program, said at the workshop that the goal was to test and ultimately provide as many biosignatures as possible. She wants many molecules potentially associated with life to be identified and then studied and restudied in the same critical way that oxygen has been — embraced for the biosignature possibilities it offers, and understood for the false positives and false negatives that might mislead.

    “What we need is an arsenal,” she said, as many ways to sniff out the byproducts of exoplanet life as that daunting task demands.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

     
  • richardmitnick 12:02 pm on June 23, 2016 Permalink | Reply
    Tags: , , Exoplanets, Qatar exoplanet survey   

    From Astronomy: “Qatar exoplanet project announces the discovery of three new exoplanets” 

    Astronomy magazine

    Astronomy Magazine

    June 23, 2016
    John Wenz

    The Qatar Exoplanet Survey announced the discovery of three new exoplanets in a paper accepted for publication at the Monthly Notices of the Royal Astronomical Society.

    The three planets are called Qatar-3b, Qatar-4b, and Qatar-5b. All three are “hot Jupiter” planets, gas giants in orbits spanning just a few Earth days around their parent stars. 3b and 5b are roughly the same mass, at 4.31 and 4.32 Jupiter masses, while 4b is about 5.85 Jupiter masses. All three are slightly larger than Jupiter as well, with 4b weighing in as the largest at 1.55 times Jupiter’s radius. 3b orbits in 2.5 days around its parent star, while 4b takes 1.8 days, and 5b takes 2.87 days. All three parent stars are roughly the size of the sun.

    The planets were discovered using the transit method, where dips in starlight give away the presence of a planet. Through the analysis, the astronomers also discovered the Qatar-5 is a metal-rich planet, meaning it comes from later, newer generations of stars that utilize heavier elements in stellar fusion alongside hydrogen-helium fusion.

    Planet transit. NASA/Ames
    Planet transit. NASA/Ames

    As the names imply, these are the third, fourth, and fifth planetary objects found by the Qatar Exoplanet Survey. All five planets discovered are hot Jupiters, which are easier to detect due to their large size and swift orbits, making transit events more common. The last planet found by the survey was in 2011. Since that time, the survey has upgraded their systems and added more telescopes.

    As the names imply, these are the third, fourth, and fifth planetary objects found by the Qatar Exoplanet Survey. All five planets discovered are hot Jupiters, which are easier to detect due to their large size and swift orbits, making transit events more common. The last planet found by the survey was in 2011. Since that time, the survey has upgraded their systems and added more telescopes.

    See the full article here .

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  • richardmitnick 12:26 pm on June 22, 2016 Permalink | Reply
    Tags: , , , Exoplanets, , Where the Wild (Planet)Things Are   

    From Astrobites: Where the Wild (Planet)Things Are 

    New research shows hot Jupiters find safety in numbers. According to radial velocity data, these giant exoplanets are more commonly found around stars in open clusters.

    Source: Where the Wild (Planet)Things Are

    Title: Search for giant planets in M67 III: excess of hot Jupiters in dense open clusters
    Authors: A. Brucalassi, L. Pasquini, R. Saglia, M.T. Ruiz, P. Bonifacio, I. Leão, B.L. Canto Martins, J.R. de Medeiros, L. R. Bedin, K. Biazzo, C. Melo, C. Lovis, and S. Randich

    First Author’s Institution: Max-Planck für extraterrestrische Physik, Garching bei München, Germany

    Status: Accepted for publication in A&A Journal Letters

    If you wanted to discover a new giant exoplanet, where would you look? New research, shows that star clusters are a good place to start, at least if you want to look for giant exoplanets close to their host star.

    Hot Jupiters are a breed of exoplanets that have masses about or larger than Jupiter and orbit a star in 10 days or less (for comparison, Mercury takes 88 days to go around the Sun). When they were first discovered, they posed a problem to planet formation models as it was thought gas giants could only form far from their host star where it was cool enough for ices to form, which allows for larger planets to be made. Since then, studies have shown these planets could form far out and migrate inwards over their lifetime. This can happen through interactions with the disk in which the planet forms (known as Type II migration), or through gravitational scattering with other planets or nearby stars.

    Brucalassi and her team decided to investigate an open cluster in the Milky Way (Messier 67) to look for hot Jupiters. Over several years they used three different telescopes (the ESO 3.6m telescope, the Hobby Eberly Telescope and the TNG on La Palma of the Canary Islands) to take high-precision spectra of 88 stars, 12 of which are binary stars. This spectra could then be analyzed for small blue- and redshifts which indicate the star is moving slightly. In this case, that movement is caused by the presence of another body, the exoplanet. This method is known as the radial velocity method and is the method that was used in the first exoplanet discoveries. To make sure that each star’s own activity wasn’t affecting its spectra, the group measured the Hα line which shows how active the star’s chromosphere is. Figure 1 shows an example of the radial velocity measurements.

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    Figure 1: Radial velocity measurements for YBP401. The coloured dots represent the different telescopes the measurements were made at. The measurements show an exoplanet with a period of just 4.08 days.

    The group’s measurements revealed a new exoplanet around the main sequence star YBP401. They were also able to get better measurements on two stars (YBP1194 and YBP1514) with known hot Jupiters. This brought the total number of hot Jupiters to 3 out of 88 stars. Although 3 might not seem like a very big number, it is larger than the number of hot Jupiters found around field stars (stars not in clusters). For the statistical analysis, Brucalassi compares the number of exoplanets with the number of main sequence and subgiant stars, i.e. stars that are not yet at the ends of their lives. Of the 88 stars, 66 are main sequence or subgiant, and of those only 53 are not binary stars. Most radial velocity studies choose to not observe binary stars so it is important to compare numbers with that in mind. A previous study from 2012 found a hot Jupiter frequency of 1.2% ± 0.38 around field stars. Brucalassi finds 4.5+4.5-2.5% when comparing with only single stars (not including binaries) in M67. To compare with statistics from the Kepler mission, binaries are included, as Kelper also surveys binaries, and the percentage for hot Jupiters in a cluster is 5.6+5.4-2.6%. The Kepler mission finds a frequency of hot Jupiters of just ~0.4%, which is considerably lower. And this trend isn’t seen just in M67. Combining radial velocity surveys for the clusters M67, Hyades, and Praesepe, there are 6 hot Jupiters in 240 surveyed stars, whereas the study from 2012 found only 12 in survey of 836 field stars.

    It’s known that systems with more metals tend to produce more planets and the star’s mass may also have an effect on planet production. However, the clusters stars and field stars are on average the same mass, so this alone cannot account for the differneces. M67 is also at solar metallicity (i.e. it’s stars tend to have the same amount of metals as our Sun) so this can also not account for the excess of hot Jupiters. Brucalassi concludes that the high number of hot Jupiters is due to the environment. Past simulations show that stars in a crowded cluster environment will experience at least one close encounter with another star, which is all that is needed to drive a Jupiter in to a closer orbit. This new research gives further evidence to this theory, putting us one step closer to understanding how exoplanets can form.

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    Figure 2: An artist’s rendition of the new hot Jupiter. Click on the image for a full animated video of the M67 cluster. Courtesy of the ESO press release (#eso1621).

     
  • richardmitnick 7:38 am on June 14, 2016 Permalink | Reply
    Tags: , , , Exoplanets   

    From ESO: “VLT Snaps An Exotic Exoplanet ‘First’ “ 

    ESO 50 Large

    European Southern Observatory

    6.13.16
    No writer credit found

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    Astronomers hunt for planets orbiting other stars (exoplanets) using a variety of methods. One successful method is direct imaging; this is particularly effective for planets on wide orbits around young stars, because the light from the planet is not overwhelmed by light from the host star and is thus easier to spot.

    This image demonstrates this technique. It shows a T-Tauri star named CVSO 30, located approximately 1200 light-years away from Earth in the 25 Orionis group (slightly northwest of Orion’s famous Belt). In 2012, astronomers found that CVSO 30 hosted one exoplanet (CVSO 30b) using a detection method known as transit photometry, where the light from a star observably dips as a planet travels in front of it.

    Planet transit. NASA
    Planet transit. NASA/Ames

    Now, astronomers have gone back to look at the system using a number of telescopes. The study combines observations obtained with the ESO’s Very Large Telescope (VLT) in Chile, the W. M. Keck Observatory in Hawaii, and the Calar Alto Observatory facilities in Spain.

    Keck Observatory, Mauna Kea, Hawaii, USA
    Keck Observatory Interior
    Keck Observatory, Mauna Kea, Hawaii, USA

    Calar Alto Observatory Province of Almería, SpainCalar Alto Observatory Interior
    Calar Alto Observatory, Province of Almería, Spain

    Using the data astronomers have imaged what is likely to be a second planet! To produce the image, astronomers exploited the astrometry provided by VLT’s NACO and SINFONI instruments.

    ESO/NACO
    ESO/NACO

    ESO SINFONI
    ESO/SINFONI

    This new exoplanet, named CVSO 30c, is the small dot to the upper left of the frame (the large blob is the star itself). While the previously-detected planet, CVSO 30b, orbits very close to the star, whirling around CVSO 30 in just under 11 hours at an orbital distance of 0.008 au, CVSO 30c orbits significantly further out, at a distance of 660 au, taking a staggering 27 000 years to complete a single orbit. (For reference, the planet Mercury orbits the Sun at an average distance of 0.39 au, while Neptune sits at just over 30 au.)

    If it is confirmed that CVSO 30c orbits CVSO 30, this would be the first star system to host both a close-in exoplanet detected by the transit method and a far-out exoplanet detected by direct imaging. Astronomers are still exploring how such an exotic system came to form in such a short timeframe, as the star is only 2.5 million years old; it is possible that the two planets interacted at some point in the past, scattering off one another and settling in their current extreme orbits.
    Link:

    Research paper by Schmidt et al.

    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”.

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  • richardmitnick 11:53 am on June 8, 2016 Permalink | Reply
    Tags: , , Exoplanets,   

    From Smithsonian: “How Would You React If We Discovered Alien Life?” 

    smithsonian
    Smithsonian.com

    Experts weigh in on what the detection of other life forms might mean to the human race

    June 7, 2016
    David Levine

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    The most habitable exoplanets discovered so far – includes Kepler 438b, which is the most Earth-like planet yet discovered. Image credit: University of Puerto Rico at Arecibo

    For more than a century, from George Melies’ A Trip to the Moon to Stephen Spielberg’s E.T. and Close Encounters to this summer’s blockbuster sequel to Independence Day, mass media, and the general public, have pondered what will happen if we ever came into contact with extraterrestrial life forms. Carl Sagan’s book Contact, and Jodie Foster’s movie of the same name, explores one possible scenario in which a Search for Extraterrestrial Intelligence (SETI) scientist (played by Foster) discovers a signal repeating a sequence of prime numbers originating from star system Vega, the 5th brightest star visible from Earth. Even if Contact’s version of an alien encounter is more likely than that presented in Spielberg’s E.T., the possibilities are worth pondering.

    And yet experts believe that the odds of receiving a radio transmission composed of prime numbers or encountering intelligent extraterrestrial life in the near future are “astronomical.” even with Hillary Clinton’s promise that if elected President, she would open up the “X-files” (Area 51).

    But the odds may be increasing due to continuing advances in technology and money. At a press conference held in April in New York City, Russian billionaire and Breakthrough Prize co-founder Yuri Milner, along with famed physicist Stephen Hawking, announced Breakthrough Starshot, a 20-year voyage to the Alpha Centauri star system. Should the existence of planets in the Alpha Centauri system be confirmed, Starshot could provide us with the best measurements of an exoplanet atmosphere we could ever hope to get this century. Milner will spend $100 million dollars to fund the project. Facebook’s founder and CEO, Mark Zuckenberg, is on the project’s board of directors.

    The goal of NASA’s Kepler Mission was to find terrestrial planets in the habitable zone of stars both near and far where liquid water and possibly life might exist. To date, Kepler has confirmed the existence of 2,337 exoplanets, including 1,284 new planets announced as of this writing. In a press release issued by NASA, chief scientist Ellen Stofan, said, “This announcement more than doubles the number of confirmed planets from Kepler. This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth.”


    Transit graph

    But what would happen if we discovered life beyond Earth?

    Christof Koch, president and chief scientific officer of the Allen Institute for Brain Science, believes most people will be excited to learn that there is intelligent life out there. “For some ‘contact” would be a wish come true and fill us with awe. But for others it would raise concerns. One can’t assume that alien cultures are by definition benevolent,” Koch says. “If we look at the history of our world, lesser civilizations were often destroyed by more advanced ones. Would the same happen to us if we encountered an advanced alien civilization?” Hawking has warned against sending messages out into space for this very reason.

    Koch has devoted his life to defining what consciousness is whether it be the internet, robots, animals, etc. Since it is doubtful that our first contact will be with humans from another planet it is important for us to understand what consciousness is so we can better understand what we do discover as we explore space. “The first discovery would probably be bacteria which might excite some scientists but not the general public. Another scenario might be a radio signal whose origin would be questioned. Was it a deliberate signal sent to us or is it random noise that can be explained scientifically? I am not holding my breath for a signal that includes prime numbers,” Koch says.

    Mary A. Voytek is the senior scientist and head of NASA’s Astrobiology Program who started Nexus for Exoplanet System Science to search for life on exoplanets. She notes that NASA scientists are currently looking at the most extreme conditions on Earth to better understand what conditions can support life throughout the universe. “If we can determine what makes a habitable planet on Earth it will help guide us to look for conditions in the universe” she says.

    Voytek notes that NASA acknowledges that the discovery of life has significance beyond science: “In order to fully understand the societal implications, we must talk to the experts-scholars in sociology and the humanities as well as theologians.”

    “When I give lectures about my work ,most people are excited about the possibility of the discovery of extraterrestrial life,” Voytek says. “This is nothing new… The ancient Greek atomists in the fourth century B.C. wrote about it. There is a quote by Democritus that I like to cite. ‘To consider the Earth as the only populated world in infinite space is as absurd as to assert that in an entire field sown with millet only one grain will grow.’”

    Douglas Vakoch, president of Messaging Extraterrestrial Intelligence (METI) has devoted much of his career with SETI to exploring what would happen on first contact and how we could even initiate it through interstellar messages. He says the majority of people believe that intelligent life is widespread in the cosmos.

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    He agrees that a discovery of something like a radio signal would result in arguments, as well as a fading lack of interest due to time. “It could take decades or even hundreds of years for us to get a response from a signal we send out. For people who are used to instant communication, this will be frustrating,” Vakoch says.

    Others think we’ll have a more dramatic experience. Susan Schneider, a professor of philosophy and cognitive science at the University of Connecticut and a fellow of the Center for Theological Inquiry, believes that if we do find intelligent life, it will be most likely be in the form of super-intelligent artificial intelligence. “For some people this would be hard to accept. Discovering a civilization that is no longer biological would be scary for us,” But Schneider is optimistic that most people will find the discovery of benevolent intelligent life exciting. “People are excited by the unknown. And the discovery of a new civilization might have many potential benefits. Perhaps an advanced civilization will share their knowledge with us,” Schneider says.

    The Catholic Church has come a long way since the days of Galileo. Pope Francis made headlines when he said he would baptize Martians. Many were surprised at the Pope’s remarks, but the Vatican has been positive about aliens for many years. Father Jose Gabriel Funes, a priest and an astronomer, views aliens as brothers and said the Church has no problem with the idea of intelligent life in the cosmos. Jesuit Brother Guy Consolmagno is the first clergyman to win the Carl Sagan Medal and the current president of the Vatican Observatory Foundation. In a 2014 article in the Christian Post, Consolmagno said “the general public will not be too surprised when life on other planets is eventually discovered, and will react in much the same way it did when news broke in the ’90s that there are other planets orbiting far off stars.”

    A similar view is held by Orthodox Jews. In an e-mail to me, Rabbi Ben Tzion Krasnianski, director of Chabad of the Upper East Side of Manhattan, wrote, “Jews believe in other life forms. The universe is populated with infinite amount of them. They are not physical, however, rather they are angels who are spiritual conscious beings that are beyond anything we could imagine. The Talmud says one angel’s mind is the equivalent of a third of the world’s population’s intelligence combined. For us it’s no surprise that we are not alone in the larger universe.”

    Vakoch said people must keep in mind that we are only at the beginning of exploration. “We have just started looking. It has only been a few hundred years that we’ve been a technologically advanced society. That’s a very small amount of time in our universe.”

    See the full article here .

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    Smithsonian magazine and Smithsonian.com place a Smithsonian lens on the world, looking at the topics and subject matters researched, studied and exhibited by the Smithsonian Institution — science, history, art, popular culture and innovation — and chronicling them every day for our diverse readership.

     
  • richardmitnick 11:56 am on May 16, 2016 Permalink | Reply
    Tags: , , Exoplanets, , Recent Kepler release of planets   

    From INVERSE: “Identify 1,284 New Exoplanets in One Fell Swoop” 

    INVERSE

    INVERSE

    May 12, 2016
    Neel V. Patel

    Before Tuesday, there were no shortage of theories about what NASA’s discovery announcement would entail. (Full disclosure: I was responsible for much of that speculation.) Then Tuesday hit and we found out exactly what the big news was: NASA scientists just confirmed the identify of 1,284 new exoplanets in the universe — including nine planets that have the potential to be habitable to life.

    It’s an announcement that has already inspired scientists and ordinary individuals around the world to ponder whether we might seriously find extraterrestrial life soon enough. But the new study raises an interesting question: what changed between the last few years and now that allowed scientists to identify so many new exoplanets all at once? Did all of these planets just show up at once? Did we develop better technology? Did the Kepler Space Telescope miraculously get better (after weirdly almost breaking down)? What gives?

    NASA/Kepler Telescope
    NASA/Kepler Telescope

    The answer: It all comes down to a new method of validating exoplanet candidates that provides ”astrophysical false positive probability calculations” for such objects, according to a new paper* published in the latest issue of The Astrophysical Journal. Basically, the new method ascribes a number to every object found by Kepler that determines the likelihood that object is an exoplanet, and not an “imposter.” Call it a planet score. The higher the number, the more likely it’s a planet.

    The new method only allows an object to move from the “candidate” category to “exoplanet” if Kepler researchers can say so with 99 percent reliability or higher.

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    This is an artist’s conception of Kepler-20e, the first planet smaller than the Earth discovered to orbit a star other than the sun. A year on Kepler-20e only lasts six days, as it is much closer to its host star than the Earth is to the sun.

    We should slow down at this point and expound on exactly how astronomers find and evaluate potential exoplanets. Basically, through Kepler and a few other instruments**, scientists stare at distant stars and measure the brightness of light emitting from those balls of fiery energy. When a star has a planet in orbit, its brightness will dim as that planet transits past it in relation to the telescope we’re using to watch it (a recent, albeit small, example is Mercury passing in front of the sun). As long as that dimming isn’t just a technical error, it’s a sign that something is passing through the neighborhood. A consistent dimming occurring regularly over time is further evidence it might be a planet.

    In the past, scientists had to pore over the brightness numbers along with assessing a variety of different data that might be attainable, like radio velocity observation or high-resolution imaging. Unfortunately, doing that kind of work is extremely time consuming, and we don’t always have the resources to find what we need.

    So in this day-and-age, we turn to computers for help. Timothy Morton, a Princeton researcher who studies exoplanets, developed a new method for exoplanet validation that combines previous exoplanet observations and the current brightness measurements scientists are gathering with Kepler.

    There are two kinds of simulations. The first looks at how the dimming compares to that from known exoplanets and imposter objects. The second goes a step further and deduces whether dimming is indicative of exoplanet behavior given what we already about how exoplanets are distributed and laid around the Milky Way.

    The two simulations are used to determine the statistical likelihood the object in question is an exoplanet. It’s a faster way of doing this work — and by all accounts, it’s even more accurate. In fact, the method is actually being used to verify previously confirmed exoplanets and determine whether they might actually be false-positives.

    This is crucial for the direction of future exoplanet research. The work accomplished since Kepler’s launch in 2009 has been huge in illustrating just how many other worlds exist in the universe — and it has given humans a staggering amount of hope we may find another habitable planet, or even alien life.

    NASA is already getting ready to launch the Transiting Exoplanet Survey Satellite (TESS) in late 2017, and the James Webb Space Telescope in 2018.

    NASA/TESS
    NASA/TESS

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    Both will play a pivotal role in exoplanet investigations by acquiring lots more data that we’ve ever dealt with. Morton’s model will help our scientists on the ground sift through that data and identify potentially habitable exoplanets faster than we could have hoped.

    Photos via NASA/Ames/JPL-Caltech, NASA/JPL-Caltech

    *SCience paper:
    FALSE POSITIVE PROBABILITIES FOR ALL KEPLER OBJECTS OF INTEREST: 1284 NEWLY VALIDATED PLANETS AND 428 LIKELY FALSE POSITIVES

    **The only other telescope that is specifically referenced, NASA/Spitzer, is referenced in the Science paper.

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    See the full article here .

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  • richardmitnick 5:40 pm on April 17, 2016 Permalink | Reply
    Tags: , , Exoplanets,   

    From CNN: “The planet hunter searching for another Earth” Sara Seager 

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    CNN

    April 15, 2016
    Jacopo Prisco

    “I want to find another Earth. That’s what I’m living for.”
    MIT astrophysicist Sara Seager has been looking at planets beyond our solar system, known as exoplanets, for almost 20 years.
    When the first ones were discovered in the 1990s, many questioned the finding and didn’t think it was real. But since then, with better technology, we have observed more than 6,000 of them, most of which are giant balls of gas.

    Today, the list grows every week.

    With so many planets now coming out of hiding, the race is on to identify one that resembles Earth: a rocky world with liquid water just like ours, and suitable to host life.
    Seager believes she knows how to make that discovery.

    ‘These aren’t planets!’

    It’s not easy to see exoplanets as you can’t just look at them through a telescope. This is due to the blinding light coming from their host stars, which can be very different in size and features compared to our sun. The process is often described as trying to spot a firefly circling a lighthouse, from thousands of miles away.

    The first ones were discovered indirectly, in 1995, by just looking at stars to see if they would wobble slightly, responding to the pull of another object’s gravity.

    At this time, Seager was a graduate student at Harvard searching for a topic for her Ph.D. and she was intrigued by the newborn field of faraway planets.
    “Since the planets were discovered indirectly, most people didn’t believe that the discoveries were real. They’d say to me ‘Why are you doing this? These aren’t planets!’,” says Seager.
    The contrarians weren’t entirely wrong: the wobble can be caused by other factors such as another star and several planet discoveries have been retracted over time for this reason.
    But then a different technique was found to make their hunt easier, called transit.

    Planet transit. NASA
    Planet transit. NASA

    This is when a planet moves in front of its host star and causes the star’s light to dim slightly.

    “One of the planets from the wobble technique showed transit: it went in front of the star at exactly the time it was predicted to and that was basically incontrovertible,” says Seager.
    Exoplanets were real.

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    Dwarfing even Jupiter – HD-106906b is a gaseous planet 11 times more massive than Jupiter. The planet is believed to have formed in the center of its solar system, before being sent flying out to the edges of the region by a violent gravitational event. No image credit.

    Alien atmospheres

    Seager did not want to simply look for distant planets. She set her sights on something more specific — their atmosphere. She was the first person to do so.
    “Atmospheres are important because they’re a way to look for signs of life: we look at gases that don’t belong and may have been produced by some life form,” she explains.
    But if seeing an exoplanet is already difficult, how do you observe an atmosphere? For this purpose the light from the star can come in handy. “When a planet transits in front of its star, we can very carefully analyze the atmosphere’s composition, thanks to the light of the star shining through it,” says Seager.

    The process becomes similar to looking at a rainbow.
    “If you look at a rainbow very closely, you see tiny little dark lines between the colors, pieces that are missing. Those lines are there because Earth’s atmosphere is taking away some of the light.”
    The dark lines are like fingerprints for specific gases and special tools can decode which ones are there. In 1999, Seager suggested that one particular element, sodium, should leave a detectable fingerprint.
    “It’s like skunk spray: a tiny bit of sodium can make a very big signature,” she says.

    Seager was right — her prediction was independently confirmed two years later using the Hubble telescope.

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    Sodium was found in the atmosphere of a “Hot Jupiter,” the name given to the first exoplanets ever discovered. These are huge spheres of gas many times larger than Earth — like our Jupiter — orbiting dangerously close to their stars, making them very hot.
    Because of their size, Hot Jupiters are the easiest exoplanets to spot, and hundreds have been found to date. But as they don’t have a solid surface, they are nothing like Earth.
    To find life, we need small, rocky planets — like ours.

    The Goldilocks Zone

    Compared to finding “Hot Jupiters”, searching for rocky planets is far more difficult, mainly because of their smaller size. And when spotting gases, it’s not sodium we’re after.

    “The number one thing we want to see in a planet’s atmosphere is water vapor,” says Seager.
    We see water vapour in some of the giant planets, like Jupiter, as they have it naturally within their atmosphere. “We have not seen that yet in a rocky planet.”
    Detecting water vapor on a rocky planet would be the tell-tale sign of a liquid ocean, and therefore the potential for life. “All life on Earth needs water, and we believe that all life needs a liquid,” says Seager.
    The need for liquid to create life is theorized due to the chemistry of molecules, as they require liquids to react and reform into other things — such as lifeforms. “Water is simply the most abundant liquid out there,” says Seager.
    For a planet to have liquid water, some basic conditions must be met. The planet must be such that its surface temperature is not too hot — or water will boil away — and not too cold — or it will freeze into ice. This all depends on its distance from the parent star: either too close, or too far.
    Astronomers call this sweet spot the “Goldilocks zone,” from the children’s tale “The Three Bears,” in which young Goldilocks likes her porridge “Not too cold, not too hot, but just right.”

    Habitable planets Current Potential Planetary Habitability Laboratory U Puerto Rico Arecibo
    Habitable planets Current Potential Planetary Habitability Laboratory U Puerto Rico Arecibo.

    These planets are not rare, but the challenge in spotting them can make it seem that way.
    “As many as one in five stars like the sun could have a planet with liquid water. And even though this number could be wrong, as things change quickly, we know for sure that small rocky planets are not rare,” says Seager.
    There may be billions of Earth-like planets in our galaxy alone.

    The galaxy’s finest

    Out of the 6,000 planets discovered so far, approximately 2,000 have been confirmed to be actual planets — work is underway on the rest — but only about 30 are considered potentially habitable.

    In 2014, NASA found the first Earth-sized planet orbiting a star in the habitable zone. This was named Kepler-186f — after the Kepler space telescope, used to spot it — and is about 500 light-years away in the constellation Cygnus, the galactic equivalent of our neighbourhood since the Milky Way is about 100,000 light years across.

    NASA/Kepler Telescope
    NASA/Kepler Telescope

    This planet is 10% larger than Earth.
    Described by NASA as “a significant step toward finding worlds like our planet Earth,” Kepler-186f orbits around a type of common star known as a red dwarf, which is about half the size of our sun.
    Then, in 2015, astronomers found the first Earth-like planet orbiting a star just like our sun, called Kepler-452b. This was dubbed Earth’s “bigger, older cousin,” as the planet is 60% larger than Earth and completes one orbit in 385 days, making its years remarkably close to our own
    With our current technology, however, it’s hard to know much more than the size of an exoplanet and how far it is from its star.
    But that’s about to change.

    New eyes in the sky

    The majority of exoplanet discoveries have been made by the Kepler space telescope, after which most of them have been named. Launched in 2009, the telescope has now entered emergency mode 75 million miles away from Earth, due to a malfunction.
    To study the atmospheres of potential Earth twins, scientists need new eyes in the sky.
    To date, Seager has only been able to study the atmospheres of a handful of exoplanets — all gas giants — but she’s involved in a new NASA program launching in 2017 to just scout the brightest nearby stars for small rocky planets in the habitable zone.


    Access mp4 video here .

    Called TESS (Transiting Exoplanet Survey Satellite), the two-year mission will accumulate data that will then be fed into the James Webb Space Telescope, the next Hubble, which is due to launch in 2018: “It’s going to be amazing,” says Seager.

    NASA/TESS
    NASA/TESS

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    The James Webb telescope — named after the head of NASA during the pioneering era of the 1960s — will look at the cosmos with unprecedented clarity thanks to its use of a primary mirror about five times larger than Hubble’s. It will also offer direct imaging of exoplanets by blocking the blinding light of their host stars with special instruments that make them more visible. This will allow Seager and other astronomers to study exoplanets like never before.
    Seager believes many of the planets in their search will be the rocky, watery worlds she’s been looking for.
    “I’m absolutely confident they’re out there.”

    See the full article here .

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  • richardmitnick 6:31 pm on April 11, 2016 Permalink | Reply
    Tags: , , , Exoplanets   

    From Carnegie: “New tool refines exoplanet search” 

    Carnegie Institution for Science
    Carnegie Institution for Science

    April 11, 2016
    No writer credit found

    Planet-hunting is an ongoing process that’s resulting in the discovery of more and more planets orbiting distant stars. But as the hunters learn more about the variety among the tremendous number of predicted planets out there, it’s important to refine their techniques. New work led by Carnegie’s Jonathan Gagné, Caltech’s Peter Gao, and Peter Plavchan from Missouri State University reports on a technological upgrade for one method of finding planets or confirming other planetary detections. The result is published by The Astrophysical Journal.

    One of the most-popular and successful techniques for finding and confirming planets is called the radial velocity method. A planet is obviously influenced by the gravity of the star it orbits; that’s what keeps it in orbit. This technique takes advantage of the fact that the planet’s gravity also affects the star in return. As a result, astronomers are able to detect the tiny wobbles the planet induces as its gravity tugs on the star. Using this method, astronomers have detected hundreds of exoplanets.

    For certain kinds of low-mass stars, however, there are limitations to the standard radial velocity method, which can cause false positives—in other words, find something that looks like a planet, but isn’t.

    To address this issue, Gagné, Gao, and Plavchan decided to use the radial velocity technique, but they examined a different, longer wavelength of light.

    “Switching from the visible spectrum to the near-infrared, the wobble effect caused by an orbiting planet will remain the same regardless of wavelength,” Gagné explained. “But looking in the near-infrared will allow us to reject false positives caused by sunspots and other phenomena that will not look the same in near-infrared as they do in visible light,”

    Radial velocity work in the near-infrared wavelengths has been conducted before, but it has trailed behind planet hunting in the visible spectrum, partially due to technical challenges. The research team was able to develop a better calibration tool to improve the overall technology for near-infrared radial velocity work, which should make it a better option going forward.

    They examined 32 low-mass stars using this technological upgrade at the NASA Infrared Telescope Facility atop Mauna Kea, Hawaii.

    NASA Infrared Telescope facility
    NASA Infrared Telescope facility Mauna Kea Hawaii USA

    Their findings confirmed several known planets and binary systems, and also identified a few new planetary candidates.

    “Our results indicate that this planet-hunting tool is precise and should be a part of the mix of approaches used by astronomers going forward,” Gao said. “It’s amazing to think that two decades ago we’d only just confirmed exoplanets actually existed and now we’re able to refine and improve those methods for further discoveries.”

    Carnegie planet hunting tool cell that contains methane gas
    Carnegie planet hunting tool cell that contains methane gas

    Other members of the team were: Guillem Anglada-Escude of University of London and the Centre for Astrophysics Research; Elise Furlan, Carolyn Brinkworth, Chas Beichman, and David Ciardi of the NASA Exoplanet Science Institute (Brinkworth also of the National Center for Atmospheric Research); Cassy Davison, Todd Henry, and Russel White of Georgia State University; Angelle Tanner of Mississippi State University; Adric Riedel and Michael Bottom of the California Institute of Technology; David Latham and John Johnson of the Harvard-Smithsonian Center for Astrophysics; Sean Mills of University of Chicago; Kent Wallace, Bertrand Mennesson, Gautam Vasisht, and Timothy Crawford of the Jet Propulsion Laboratory; Kaspar Von Braun and Lisa Prato of Lowell Observatory; Stephen Kane of San Francisco State University; Eric Mamajek of University of Rochester; Bernie Walp of the NASA Dryden Flight Research Center; Raphael Rougeot of the Euroopean Space Research and Technology Centre; Claire Geneser of Missouri State; and Joseph Catanzarite of NASA Ames Research Center.

    This work was supported by an Infrared Processing and Analysis Center (IPAC) fellowship, a grant from the Fond de Recherche Québécois – Nature et Technologie and the Natural Science, a grant from the Engineering Research Council of Canada, an iREx postdoctoral Fellowship, and a JPL Research and Technology Development Grant. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by the National Aeronautics and Space Administration (NASA) through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    Carnegie Institution of Washington Bldg

    Andrew Carnegie established a unique organization dedicated to scientific discovery “to encourage, in the broadest and most liberal manner, investigation, research, and discovery and the application of knowledge to the improvement of mankind…” The philosophy was and is to devote the institution’s resources to “exceptional” individuals so that they can explore the most intriguing scientific questions in an atmosphere of complete freedom. Carnegie and his trustees realized that flexibility and freedom were essential to the institution’s success and that tradition is the foundation of the institution today as it supports research in the Earth, space, and life sciences.

     
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