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  • richardmitnick 4:45 pm on December 17, 2014 Permalink | Reply
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    From NASA/Kepler: “Mission Manager Update: K2 Campaign 3 underway “ 

    NASA Kepler Logo

    NASA Kepler Telescope
    NASA/Kepler

    December 16, 2014

    Kepler and K2 have kept the team very busy over the past couple of months, and we are overdue on providing an update on the great work that’s been going on. The spacecraft continues to perform superbly in its two-wheel configuration and is actively collecting data for the K2 mission, while the team has continued to tune the operations to improve the science yield. Meanwhile, we continue analyzing the full four years of Kepler data and delivering the new K2 data to the public at the Mikulski Archive for Space Telescopes (MAST).

    K2 is now in its seventh month of operation and began its third campaign on Nov. 12. The Campaign 3 field-of-view includes more than 16,000 target stars, which can be searched for exoplanets and examined for an array of astrophysical information. This campaign also includes observations of a number of objects within our own solar system, including the dwarf planet (225088) 2007 OR10, the largest known body without a name in the solar system, and the planet Neptune and its moon Nereid.

    a
    Artist’s impression of (225088) 2007 OR10

    Campaign 0 data have been delivered to MAST, and Campaign 1 data will follow later this month. Campaign 2 will be processed with a scheduled delivery in February 2015.

    Target proposals for Campaigns 6 and 7 are now being accepted. The deadline for K2 Cycle-2 Stage-1 Guest Observer proposals is 11:59 p.m. EST on Jan. 16, 2015. For the full schedule of operational milestones see the K2 Mission Timeline.

    On Oct. 20, the Kepler spacecraft joined the fleet of NASA science assets that observed distant Oort Cloud native Comet Siding Spring as it passed through K2’s Campaign 2 field-of-view on its long journey around the sun. The data collected by K2 will add to the study of the comet, giving scientists an invaluable opportunity to learn more about the materials, including water and carbon compounds, that existed during the formation of the solar system 4.6 billion years ago.

    o
    Impression of the Oort Cloud

    c
    Comet Siding Spring

    To learn more about the K2 mission visit the Kepler Science Center website.

    While K2 operations proceed, the Kepler team continues work on finalizing the data processing and products for the prime mission. The team is also anticipating another mission milestone: the 1,000th exoplanet discovered by Kepler.

    To-date Kepler has identified more than 4,000 planet candidates, and 996 have been verified as bona fide planets. For the latest Kepler exoplanet and candidate statistics, visit the NASA Exoplanet Archive.

    In January 2015, members of the team will participate in the 225th meeting of the American Astronomical Society in Seattle. We look forward to the meeting and sharing the latest scientific results using Kepler and K2 data.

    The following are highlights of recent research using Kepler and K2 data that have been accepted by a peer-review journal:

    High-resolution Multi-band Imaging for Validation and Characterization of Small Kepler Planets (Everett et al., 2014) – The paper presents a new method for validating Kepler candidates using high-resolution imaging and validates five new small planets in two systems: Kepler-430 and Kepler-431.
    Planet Hunters VII. Discovery of a New Low-Mass, Low-Density Planet (PH3 c) Orbiting Kepler-289 (Schmitt et al., 2014) – The paper confirms the discovery of a third planet orbiting host star Kepler-239 by Planet Hunters, a volunteer citizen scientist effort. This marks the group’s third confirmed planet since its inception in December 2010.
    A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission (Vanderburg et al., 2014) – The publication presents a technique for generating light curves from K2 pixel data. The research finds that the technique produces data with noise properties similar to Kepler targets at the same magnitude.

    Regards,
    Charles Sobeck

    See the full article here.

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    The Kepler Mission, NASA Discovery mission #10, is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone→ and determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets.
    The operations phase of the Kepler mission is managed for NASA by the Ames Research Center, Moffett Field, CA. NASA’s Jet Propulsion Laboratory (JPL), Pasadena, CA, managed the mission through development, launch and the start of science operations. Dr. William Borucki of NASA Ames is the mission’s Science Principal Investigator. Ball Aerospace and Technologies Corp., Boulder, CO, developed the Kepler flight system.

    In October 2009, oversight of the Kepler project was transferred from the Discovery Program at NASA’s Marshall Space Flight Center, Huntsville, AL, to the Exoplanet Exploration Program at JPL

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  • richardmitnick 11:44 am on December 17, 2014 Permalink | Reply
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    From MIT: “Life on an aquaplanet” 


    MIT News

    December 17, 2014
    Jennifer Chu | MIT News Office

    Nearly 2,000 planets beyond our solar system have been identified to date. Whether any of these exoplanets are hospitable to life depends on a number of criteria. Among these, scientists have thought, is a planet’s obliquity — the angle of its axis relative to its orbit around a star.

    Earth, for instance, has a relatively low obliquity, rotating around an axis that is nearly perpendicular to the plane of its orbit around the sun. Scientists suspect, however, that exoplanets may exhibit a host of obliquities, resembling anything from a vertical spinning top to a horizontal rotisserie. The more extreme the tilt, the less habitable a planet may be — or so the thinking has gone.

    Now scientists at MIT have found that even a high-obliquity planet, with a nearly horizontal axis, could potentially support life, so long as the planet were completely covered by an ocean. In fact, even a shallow ocean, about 50 meters deep, would be enough to keep such a planet at relatively comfortable temperatures, averaging around 60 degrees Fahrenheit year-round.

    1
    Illustration: Christine Daniloff/MIT

    David Ferreira, a former research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS), says that on the face of it, a planet with high obliquity would appear rather extreme: Tilted on its side, its north pole would experience daylight continuously for six months, and then darkness for six months, as the planet revolves around its star.

    “The expectation was that such a planet would not be habitable: It would basically boil, and freeze, which would be really tough for life,” says Ferreira, who is now a lecturer at the University of Reading, in the United Kingdom. “We found that the ocean stores heat during summer and gives it back in winter, so the climate is still pretty mild, even in the heart of the cold polar night. So in the search for habitable exoplanets, we’re saying, don’t discount high-obliquity ones as unsuitable for life.”

    Details of the group’s analysis are published in the journal Icarus. The paper’s co-authors are Ferreira; Sara Seager, the Class of 1941 Professor in EAPS and MIT’s Department of Physics; John Marshall, the Cecil and Ida Green Professor in Earth and Planetary Sciences; and Paul O’Gorman, an associate professor in EAPS.

    Tilting toward a habitable exoplanet

    Ferreira and his colleagues used a model developed at MIT to simulate a high-obliquity “aquaplanet” — an Earth-sized planet, at a similar distance from its sun, covered entirely in water. The three-dimensional model is designed to simulate circulations among the atmosphere, ocean, and sea ice, taking into the account the effects of winds and heat in driving a 3000-meter deep ocean. For comparison, the researchers also coupled the atmospheric model with simplified, motionless “swamp” oceans of various depths: 200 meters, 50 meters, and 10 meters.

    The researchers used the detailed model to simulate a planet at three obliquities: 23 degrees (representing an Earth-like tilt), 54 degrees, and 90 degrees.

    For a planet with an extreme, 90-degree tilt, they found that a global ocean — even one as shallow as 50 meters — would absorb enough solar energy throughout the polar summer and release it back into the atmosphere in winter to maintain a rather mild climate. As a result, the planet as a whole would experience spring-like temperatures year round.

    “We were expecting that if you put an ocean on the planet, it might be a bit more habitable, but not to this point,” Ferreira says. “It’s really surprising that the temperatures at the poles are still habitable.”

    A runaway “snowball Earth”

    In general, the team observed that life could thrive on a highly tilted aquaplanet, but only to a point. In simulations with a shallower ocean, Ferreira found that waters 10 meters deep would not be sufficient to regulate a high-obliquity planet’s climate. Instead, the planet would experience a runaway effect: As soon as a bit of ice forms, it would quickly spread across the dark side of the planet. Even when this side turns toward the sun, according to Ferreira, it would be too late: Massive ice sheets would reflect the sun’s rays, allowing the ice to spread further into the newly darkened side, and eventually encase the planet.

    “Some people have thought that a planet with a very large obliquity could have ice just around the equator, and the poles would be warm,” Ferreira says. “But we find that there is no intermediate state. If there’s too little ocean, the planet may collapse into a snowball. Then it wouldn’t be habitable, obviously.”

    Darren Williams, a professor of physics and astronomy at Pennsylvania State University, says past climate modeling has shown that a wide range of climate scenarios are possible on extremely tilted planets, depending on the sizes of their oceans and landmasses. Ferreira’s results, he says, reach similar conclusions, but with more detail.

    “There are one or two terrestrial-sized exoplanets out of a thousand that appear to have densities comparable to water, so the probability of an all-water planet is at least 0.1 percent,” Williams says. “The upshot of all this is that exoplanets at high obliquity are not necessarily devoid of life, and are therefore just as interesting and important to the astrobiology community.”

    See the full article here.

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  • richardmitnick 11:30 am on December 5, 2014 Permalink | Reply
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    From U Washington 

    U Washington

    University of Washington

    December 2, 2014
    Peter Kelley

    Planets orbiting close to low-mass stars — easily the most common stars in the universe — are prime targets in the search for extraterrestrial life.

    But new research led by an astronomy graduate student at the University of Washington indicates some such planets may have long since lost their chance at hosting life because of intense heat during their formative years.

    m
    Illustration of a low-mass, M dwarf star, seen from an orbiting rocky planet. NASA / JPL

    Low-mass stars, also called M dwarfs, are smaller than the sun, and also much less luminous, so their habitable zone tends to be fairly close in. The habitable zone is that swath of space that is just right to allow liquid water on an orbiting planet’s surface, thus giving life a chance.

    Planets close to their host stars are easier for astronomers to find than their siblings farther out. Astronomers discover and measure these worlds by studying the slight reduction in light when they transit, or pass in front of their host star; or by measuring the star’s slight “wobble” in response to the planet’s gravity, called the radial velocity method.

    But in a paper to be published in the journal Astrobiology, doctoral student Rodrigo Luger and co-author Rory Barnes, a UW research assistant professor, find through computer simulations that some planets close to low-mass stars likely had their water and atmospheres burned away when they were still forming.

    “All stars form in the collapse of a giant cloud of interstellar gas, which releases energy in the form of light as it shrinks,” Luger said. “But because of their lower masses, and therefore lower gravities, M dwarfs take longer to fully collapse — on the order of many hundreds of millions of years.”

    “Planets around these stars can form within 10 million years, so they are around when the stars are still extremely bright. And that’s not good for habitability, since these planets are going to initially be very hot, with surface temperatures in excess of a thousand degrees. When this happens, your oceans boil and your entire atmosphere becomes steam.”

    Also boding ill for the atmospheres of these worlds is the fact that M dwarf stars emit a lot of X-ray and ultraviolet light, which heats the upper atmosphere to thousands of degrees and causes gas to expand so quickly it leaves the planet and is lost to space, Luger said.

    “So, many of the planets in the habitable zones of M dwarfs could have been dried up by this process early on, severely decreasing their chance of actually being habitable.”

    A side effect of this process, Luger and Barnes write, is that ultraviolet radiation can split up water into its component hydrogen and oxygen atoms. The lighter hydrogen escapes the atmosphere more easily, leaving the heavier oxygen atoms behind. While some oxygen is clearly good for life, as on Earth, too much oxygen can be a negative factor for the origin of life.

    “Rodrigo has shown that this prolonged runaway greenhouse phase can produce huge atmospheres full of oxygen — like, 10 times denser than that of Venus and all oxygen,” said Barnes. “Searches for life often rely on oxygen as a tracer of extraterrestrial life — so the abiological production of such huge quantities of oxygen could confound our search for life on exoplanets.”

    Luger said the working title of their paper was Mirage Earths.

    “Because of the oxygen they build up, they could look a lot like Earth from afar — but if you look more closely you’ll find that they’re really a mirage; there’s just no water there.”

    The research was funded by NASA’s Astrobiology Institute, through the Virtual Planetary Laboratory, headquartered at the UW.

    See the full article here.

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    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.

    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 3:01 pm on December 2, 2014 Permalink | Reply
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    From Keck: “Scientists Accurately Quantify Dust Around Planets in Search for Life” 

    Keck Observatory

    Keck Observatory

    Keck Observatory

    December 2, 2014
    SCIENCE CONTACT:
    Bertrand Mennesson, PhD
    Jet Propulsion Laboratory
    (818)-354-0494
    bertrand.mennesson@jpl.nasa.gov

    MEDIA CONTACT
    Steve Jefferson
    Communications Officer
    W. M. Keck Observatory
    808.881.3827
    sjefferson@keck.hawaii.edu

    A new study from the Keck Interferometer, a former NASA project that combined the power of the twin W. M. Keck Observatory telescopes atop Mauna Kea, Hawaii, has brought exciting news to planet hunters. After surveying nearly 50 stars from 2008 to 2011, scientists have been able to determine with remarkable precision how much dust is around distant stars – a big step closer into finding planets than might harbor life. The discovery is being published in the Astrophysical Journal online, on December 8th.

    two
    Credit: NASA/JPL-Caltech
    A dusty planetary system (left) is compared to another system with little dust in this artist’s conception. Dust can make it difficult for telescopes to image planets because light from the dust can outshine that of the planets. Dust reflects visible light and shines with its own infrared, or thermal, glow. As the illustration shows, planets appear more readily in the planetary system shown at right with less dust. Research with the NASA-funded Keck Interferometer, a former NASA key science project that combined the power of the twin telescopes of the W. M. Keck Observatory atop Mauna Kea, Hawaii, shows that mature, sun-like stars appear to be, on average, not all that dusty. This is good news for future space missions wanting to take detailed pictures of planets like Earth and seek out possible signs of life.

    “This was really a mathematical tour de force,” said Peter Wizinowich, Interferometer Project Manager for Keck Observatory. “This team did something that we seldom see in terms of using all the available statistical techniques to evaluate the combined data set. They were able to dramatically reduce all the error bars, by a factor of 10, to really understand the amount of dust around these systems.”

    The Keck Interferometer was built to seek out this dust, and to ultimately help select targets for future NASA Earth-like planet-finding missions.

    Like planets, dust near a star is also hard to see. Interferometry is a high-resolution imaging technique that can be used to block out a star’s light, making the region nearby easier to observe. Light waves from the precise location of a star, collected separately by the twin 10-meter Keck Observatory telescopes, are combined and canceled out in a process called nulling.

    “If you don’t turn off the star, you are blinded and can’t see dust or planets,” said co-author Rafael Millan-Gabet of NASA’s exoplanet Science Institute at the California Institute of Technology in Pasadena, California, who led the Keck Interferometer’s science operations system.

    “Dust is a double-edged sword when it comes to imaging distant planets,” explained Bertrand Mennesson, lead author of the study who works at NASA’s Jet Propulsion Laboratory, Pasadena, California. “The presence of dust is a signpost for the planet formation process, but too much dust can block our view.” Mennesson has been involved in the Keck Interferometer project since its inception more than 10 years ago, both as a scientist and as the optics lead for one of its instruments.

    “Using the two Keck telescopes in concert and interfering their light beams, it is possible to distinguish astronomical objects much closer to each other than when using a single Keck telescope,” Mennesson said. “However, there is an additional difficulty when searching for warm dust in the immediate stellar environment: it generally contributes very little emission compared to the star, and that is when nulling interferometry comes into play.”

    In addition to requiring high performance from a large number of hardware and software subsystems, the nuller mode requires them to work smoothly together as a single, integrated system, according to Mark Colavita, the Keck Interferometer System Architect. “The nulling mode of the interferometer uses starlight across a wide range of wavelengths, including visible light for the adaptive optics to correct the telescope wave-fronts, near-infrared light to stabilize the path-lengths, and mid-infrared light for the nulling science measurements.”

    Planet Hunting

    Ground- and space-based telescopes have already captured images of exoplanets, or planets orbiting stars beyond our sun. These early images, which show giant planets in cool orbits far from the glow of their stars, represent a huge technological leap. The glare from stars can overwhelm the light of planets, like a firefly buzzing across the sun. So, researchers have developed complex instruments to block the starlight, allowing information about a planet’s shine to be obtained.

    The next challenge is to image smaller planets in the “habitable” zone around stars where possible life-bearing Earth-like planets outside the solar system could reside. Such a lofty goal may take decades, but researchers are already on the path to get there, developing new instruments and analyzing the dust kicked up around stars to better understand how to snap crisp planetary portraits. Scientists want to find out: Which stars have the most dust? And how dusty are the habitable zones of sun-like stars?

    In the latest study, nearly 50 mature, sun-like stars were analyzed with high precision to search for warm, room-temperature dust in their habitable zones. Roughly half of the stars selected for the study had previously shown no signs of cool dust circling in their outer reaches. This outer dust is easier to see than the inner, warm dust due to its greater distance from the star. Of this first group of stars, none were found to host the warm dust, making them good targets for planet imaging, and a good indication that other relatively dust-free stars are out there.

    The other stars in the study were already known to have significant amounts of distant cold dust orbiting them. In this group, many of the stars were found to also have the room-temperature dust. This is the first time a link between the cold and warm dust has been established. In other words, if a star is observed to have a cold belt of dust, astronomers can make an educated guess that its warm habitable zone is also riddled with dust, making it a poor target for imaging smaller planets in the ‘habitable zone’ around stars, or exo-Earths.

    “We want to avoid planets that are buried in dust,” said Mennesson.

    Like a busy construction site, the process of building planets is messy. It’s common for young, developing star systems to be covered in dust. Proto-planets collide, scattering dust. But eventually, the chaos settles and the dust clears – except in some older stars. Why are these mature stars still laden with warm dust in their habitable zones?

    The newfound link between cold and warm dust belts helps answer this question.

    “The outer belt is somehow feeding material into the inner warm belt,” said Geoff Bryden of JPL, a co-author of the study. “This transport of material could be accomplished as dust smoothly flows inward, or there could be larger cometary bodies thrown directly into the inner system.”

    The Keck Interferometer began construction in 1997, and finished its mission in 2012. It was developed by JPL, the Keck Observatory and the NASA Exoplanet Science Institute at Caltech. It was funded by NASA as a part of the Exoplanet Exploration Program with telescope and instrument operations managed by the W. M. Keck Observatory.

    See the full article here.

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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

    Keck NASA

    Keck Caltech

     
  • richardmitnick 6:54 pm on December 1, 2014 Permalink | Reply
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    From phys.org: “Observing solar system worlds as if they were distant exoplanets” 

    physdotorg
    phys.org

    December 1, 2014
    Adam Hadhazy

    “It takes one to know one,” as the old truism goes. When it comes to unraveling the mysteries of far-off exoplanets, the same holds true—one more reason why astronomers want to thoroughly understand the local planets right here in our Solar System.

    A new scientific paper moves the ball forward in this regard by simulating how several rocky Solar System bodies would look if glimpsed at the light-years distance of alien worlds. Across such great spans, exoplanets are just dim specks. But what little light does get to us could, the study suggests, imply intriguing details about their surface features, provided we know what to look for.

    Previous studies of Earth have demonstrated that oceans, continents and ice caps bounce back strikingly different amounts of light into space. Models demonstrate that even from considerable distances, an observer would be able to pick out the different types of surface materials of water, land and ice.

    The new study extends this concept to solid worlds unlike Earth, such as Mars and the Galilean moons, to broaden our basis for comparison.

    “We eventually want to investigate the surface environments of Earth-like exoplanets, and for this purpose the observable signatures of Earth have been widely studied,” said lead author Yuka Fujii, a postdoctoral research scientist at the Tokyo Institute of Technology’s Earth-Life Science Institute. “To interpret the data of unknown planets obtained in the future, we also need to know the possible variety of observable features of other, non-Earth-like planets.”

    The study, titled Geology and Photometric Variation of Solar System Bodies with Minor Atmospheres: Implications for Solid Exoplanets, has been accepted for publication in the journal Astrobiology.

    Staring right at you

    Although astronomers have discovered nearly 2,000 exoplanets to date, we know very little about any of them. For the vast majority, we merely possess either a mass or a size measurement. Exoplanets are simply too remote and faint for our current suite of instruments to glean tangible, worldly properties like color, surface features and cloud cover.

    Our most detailed exoplanetary information so far has it that a handful of these worlds harbor gases, such as water vapor and carbon dioxide, in their atmospheres. That knowledge comes from signatures imprinted by those gases onto light that has passed through the atmosphere. The measurement, though, is indirect. The light assumed to pertain to the exoplanet is separated out from the overwhelming glare of its star.

    Fujii’s study goes a step further in considering worlds that we will “directly image.” The distinction: The light from a directly imaged world is just from the world itself, not inferred from within a star’s comparatively blinding glare. This happens to be how we study planets in the Solar System: We look right at them rather than teasing their presence out from a blaze of light.

    Less than two dozen exoplanets have been directly imaged to date. The potential advantage of this technique is to be able to distinguish features on small, rocky exoplanets, the best places we think for life to arise.

    Today’s top-notch telescopes, like the Hubble and Spitzer Space Telescopes, will not be up to this task, however. Instead, we must wait for next-generation telescopes and specialized instruments that can collect the planetary light more efficiently than today’s instruments, separately from the host star. Several of these instruments in the works may utilize the James Webb Space Telescope., slated for launch in 2018, and the “thirty meter” class of telescopes on the ground.

    NASA Hubble Telescope

    NASA Spitzer Telescope

    NASA Webb Telescope
    NASA/Webb

    ESO E-ELT
    ESO/E-ELT

    TMT
    TMT

    Giant Magellan Telescope
    Giant Magellan Telescope

    From here to there

    To lay a foundation for this future work, Fujii’s study rendered Solar System worlds as far-off, dim exo-worlds. Fujii and colleagues collected existing data, as well as some fresh observations of Mercury, the Moon, Mars and the four Galilean moons of Jupiter (Io, Europa, Ganymede and Callisto).

    f
    The Hubble Space Telescope’s view of the star Fomalhaut and a directly imaged object encircling it, Fomalhaut b, thought to be an exoplanet. Credit: NASA, ESA, P. Kalas, J. Graham, E. Chiang, E. Kite (University of California, Berkeley), M. Clampin (NASA Goddard Space Flight Center), M. Fitzgerald (Lawrence Livermore National Laboratory), and K. Stapelfeldt and J. Krist (NASA Jet Propulsion Laboratory)

    Because these bodies are all relatively close, detailed maps have been made of their surfaces, consisting of thousands of pixels. Exoplanets, however, owing to their distance, can occupy only a single pixel—a so-called point source. To render Solar System bodies as point sources, Fujii averaged the total color, or brightness, of their numerous pixels down to a single pixel. (Ice, for instance, reflects more light than land, so it has a brighter color.)

    As a world rotates, the brightness of this single pixel varies over time if the world’s surface is not all the same. For example, when Earth rotates such that the vast Pacific Ocean faces toward an observer, the planet’s overall brightness changes compared to when, say, the giant landmass of Asia swings into view.

    “Due to the spin rotation, we see different slices of the surface at different times,” said Fujii. “So if the brightness varies as the planet rotates, it indicates non-uniform surface material.”

    Telltale light changes

    The various worlds considered in the study did demonstrate average color variations over time that could be explicitly tied to factors affecting their surface compositions.

    For a waterless body like the Moon, regions with potentially large contrasts to elsewhere on the lunar surface are “maria,” the dark lava fields that form the pareidolic “Man in the Moon” patterns. And sure enough, the Moon stood out as a Solar System object with discernibly dissimilar light-reflecting regions.

    Mercury, though it has a fairly uniformly gray color, has smooth plains covering 40 percent of its otherwise heavily cratered surface. The effect on its light reflectance patterns was similar in some ways, but not as dramatic as that of the two-tone Moon.

    Io, meanwhile, jumped out thanks to its raging volcanoes, which have slathered the surface in yellows and reds, famously looking like pizza. The brightnesses of the other three Galilean moons, Europa, Ganymede and Callisto, fluctuated because of patches of darker material deposited on lighter, water ice. Ganymede’s light patterns also hinted at its rumpled surface, with grooves and ridges owing to past internal heating events.

    Mars, interestingly, had a lot of light variability at longer wavelengths, because fine-grained particles on the Red Planet’s surface scatter these forms of light. The iron oxides, or rust, that covers a significant portion of Mars, however, are efficient at absorbing shorter wavelength light. So the notable presences and absences of certain wavelength of light told a convincing tale of what large expanses of the Mars’ surface are like.

    Overall, over the course of a single rotation of a planet or moon, these geological characteristics caused changes in brightness ranging from five percent to a quote noticeable 50 percent.

    “Other Solar System bodies are also distinct, exhibiting various interesting surface features, some of which affect their characteristic surface colors, highlighting the amazing diversity that awaits future reconnaissance, and thus the need for continued study,” said Fujii.

    Getting the basics down

    i
    The pockmarked, colorful surface of Io. Credit: NASA

    The results point to how we might, with direct imaging, begin to pick out exoplanets with distinct, yet familiar geologic histories and perhaps even habitable conditions.

    One major aspect that the study sidesteps is the lack of atmospheres in the chosen worlds. Intervening gases, and especially clouds, can make surface characterization difficult or impossible using direct imaging. For example, the thick, cloudy atmospheres of Venus or Saturn’s moon, Titan, completely hide their faces.

    But in the case of Earth, although clouded here and there, the primary surface entities of continents, oceans and ice caps, can clearly be identified even at tremendous distance, the evidence suggests.

    Although indirect atmospheric characterization of habitable exo-worlds will surely precede direct surface imaging, both of these techniques will need to be brought to bear to figure out if, and what sort of, alien life has developed.

    v
    A super-Venus, illustrated on the left, would have a very different-looking surface brightness-wise from a super-Earth, drawn at right, with varying surface features, such as oceans and continents. Credit: NASA/JPL-Caltech/AMES

    “We think this kind of survey is useful,” said Fujii, “because in terms of astrobiology, we will be interested in the details of the planetary surfaces after we know the atmospheric profiles.”

    Along with setting aside atmospheres for now, another caveat of Fujii’s study is that the first solid, potentially life-friendly exo-worlds we will likely directly image will be significantly heftier than Earth. These “super-Earths” are on the order of up to twice Earth’s width and several times its mass. Per their bigness, super-Earths will be easier to find and examine.

    “We wish we had super-Earth counterparts in the Solar System, because then we would definitely study their properties first,” said Fujii.

    Even so, building upon Fujii’s results, astronomers should be well-placed to get a bead on super-Earth surfaces—at least compared to familiar Solar System objects.

    “Now that we have a handful of planets and satellites in the Solar System whose properties we know in some detail,” said Fujii, “we want to make the most of that knowledge, which we consider as necessary target practice.”

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  • richardmitnick 6:21 pm on December 1, 2014 Permalink | Reply
    Tags: , , , , Exoplanets   

    Planet X – Four Times the Size of Earth – Science or Science Fiction? 

    A Planet Four Times the Size of Earth Lurking Far Beyond Neptune – Is NASA Hiding Planet-X?

    The evidence for ‘Planet X’ – the mysterious hypothesised planet on the edge of our solar system – has taken a new turn thanks to the mathematics of a noted astronomer.
    Rodney Gomes, an astronomer at the National Observatory of Brazil in Rio de Janeiro, says the irregular orbits of small icy bodies beyond Neptune imply that a planet four times the size of Earth is swirling around our sun in the fringes of the solar system.

    Gomes measured the orbits of 92 Kuiper Belt objects – small bodies and dwarf planets – and said that six objects appeared to be tugged off-course compared to their expected orbits.

    kb
    Known objects in the Kuiper belt, derived from data from the Minor Planet Center. Objects in the main belt are colored green, whereas scattered objects are colored orange. The four outer planets are blue. Neptune’s few known trojans are yellow, whereas Jupiter’s are pink. The scattered objects between Jupiter’s orbit and the Kuiper belt are known as centaurs. The scale is in astronomical units. The pronounced gap at the bottom is due to difficulties in detection against the background of the plane of the Milky Way.

    Speaking at a meeting of the American Astronomical Society Rodney Gomes presented complex calculations and computer models, indicating the existence of this world as a genuine possibility.

    He told astronomers at the AAS that the most likely reason for the irregular orbits was a ‘planetary-mass solar companion’ – a distant body of planet size that is powerful enough to move the Kuiper belt objects.

    He suggested the planet would be four times bigger than Earth – around the size of Nepture and would be 140 billion miles from the sun, or about 1,500 times further than the Earth.http://tinyurl.com/7jtngcc

    Planetary scientist Rodney Gomes of the National Observatory in Rio de Janeiro suggested that Planet X might be “extrasolar.” Many of the sun’s siblings have their own planets, and it’s possible that these stars stole planets from each others’ gravitational pull.

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  • richardmitnick 11:19 am on November 29, 2014 Permalink | Reply
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    From Tuscon.com: “NASA needs Kitt Peak telescope for exoplanet duty” 

    t
    tuscon.com

    November 28, 2014
    Tom Beal

    NASA needed an earthbound location for following up the exoplanet discoveries of its orbiting telescopes just when the National Science Foundation was looking to unload its share of the WIYN Telescope on Kitt Peak.

    NOAO WIYN Telescope
    w
    NOAO KItt Peak WIYN telescope

    “Our friends at NSF came over and said … ‘Any interest in a joint venture before we pull the plug on it?’” said Douglas Hudgins, program scientist for exoplanet exploration at NASA’s Astrophysics Division.

    Hudgins said NASA looked at WIYN’s capabilities and decided it was a good match for its need to learn more about planets it had found orbiting distant stars with its Kepler Space Telescope and for future discoveries made closer by with Kepler’s K2 mission.

    NASA Kepler Telescope
    NASA/Kepler

    It also plans to equip the 3.5-meter telescope with an instrument that will perform “extreme precision Doppler spectrography,” said Hudgins.

    It will be used to follow up discoveries that will be made around nearby stars in NASA’s upcoming TESS mission, he said.

    NASA TESS
    NASA/TESS

    TESS, the Transiting Exoplanet Survey Satellite, is expected to launch by 2018.

    The National Optical Astronomy Observatory (NOAO) will continue to operate the telescope and will give its 40 percent share of its time to projects proposed by individual scientists that support NASA’s exoplanet program.

    The telescope’s other partners are the universities of Wisconsin, Indiana and Missouri. The “Y” in its name came from original partner Yale University.

    WIYN, which saw first light in 1994, is the second largest optical telescope on Kitt Peak.

    “The WIYN is a really great telescope,” said Hudgins. Kitt Peak remains a good site for astronomy and the WIYN occupies “the best spot” there, he said.

    NASA’s Kepler has found 4,178 exoplanet candidates using the transit method, which records a diminution of a star’s light when a planet passes in front of it.

    It has confirmed 995 exoplanets in follow-up observations, which involve a measurement of the planet’s radial velocity — its tug on the host star. A few have been directly observed by the largest telescopes on Earth and in space.

    The radial velocity measurement requires “very high precision,” said Hudgins.

    It measures the slight shift toward the blue part of the spectrum when a planet passes in front of a star and tugs it toward the observer, and the slight shift toward red when it passes behind.

    The smaller the planet, the more precision needed, said Hudgins, and the new instrument will be capable of measuring the tug from small, possibly Earthlike planets — the ultimate targets of the hunt.

    Only a handful of such instruments exist, said Hudgins. “This is going to be the first such instrument openly available to the U.S. scientific community.”

    NASA’s involvement is the happiest possible ending for WIYN and NOAO, said Kitt Peak Director Lori Allen.

    It adds capabilities while preserving open access, she said.

    John Salzer, chair of the Department of Astronomy at Indiana University, called the arrangement “an outstanding resolution to our funding crisis.”

    In an email, Salzer said NASA’s involvement has “significant positive ramifications for the WIYN university partners in terms of new science opportunities.”

    See the full article here

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  • richardmitnick 10:46 pm on November 27, 2014 Permalink | Reply
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    From SPACE.com: “Found! First Earth-Size Planet That Could Support Life” 

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    SPACE.com

    For the first time, scientists have discovered an Earth-size alien planet in the habitable zone of its host star, an “Earth cousin” that just might have liquid water and the right conditions for life.This artist illustration shows what it might be like to stand on the surface of the planet Kepler-186f, the first-ever Earth-size planet to be found in the habitable zone of its star.
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    Credit: Danielle Futselaar

    The newfound planet, called Kepler-186f, was first spotted by NASA’s Kepler space telescope and circles a dim red dwarf star about 490 light-years from Earth. While the host star is dimmer than Earth’s sun and the planet is slightly bigger than Earth, the positioning of the alien world coupled with its size suggests that Kepler-186f could have water on its surface, scientists say.

    m
    Comparison of best-fit size of the exoplanet Kepler-186 f with the Solar System planet Earth, as reported in the Open Exoplanet Catalogueas of 2014-04-20.

    NASA Kepler Telescope
    NASA/Kepler

    “One of the things we’ve been looking for is maybe an Earth twin, which is an Earth-size planet in the habitable zone of a sunlike star,” Tom Barclay, Kepler scientist and co-author of the new exoplanet research, told Space.com. “This [Kepler-186f] is an Earth-size planet in the habitable zone of a cooler star. So, while it’s not an Earth twin, it is perhaps an Earth cousin. It has similar characteristics, but a different parent.”

    i
    This artist illustration shows the planet Kepler-186f, the first Earth-size alien planet discovered in the habitable zone of its star.
    Credit: NASA Ames/SETI Institute/JPL-CalTech

    Potentially habitable planet

    Scientists think that Kepler-186f — the outermost of five planets found to be orbiting the star Kepler-186 — orbits at a distance of 32.5 million miles (52.4 million kilometers), theoretically within the habitable zone for a red dwarf.

    Earth orbits the sun from an average distance of about 93 million miles (150 million km), but the sun is larger and brighter than the Kepler-186 star, meaning that the sun’s habitable zone begins farther out from the star by comparison to Kepler-186.

    “This is the first definitive Earth-sized planet found in the habitable zone around another star,” Elisa Quintana, of the SETI Institute and NASA’s Ames Research Center and the lead author of a new study detailing the findings, said in a statement.

    Other planets of various sizes have been found in the habitable zones of their stars. However, Kepler-186f is the first alien planet this close to Earth in size found orbiting in that potentially life-supporting area of an extrasolar system, according to exoplanet scientists.

    An historic discovery

    “This is an historic discovery of the first truly Earth-size planet found in the habitable zone around its star,” Geoff Marcy, an astronomer at the University of California, Berkeley, who is unaffiliated with the research, told Space.com via email. “This is the best case for a habitable planet yet found. The results are absolutely rock-solid. The planet itself may not be, but I’d bet my house on it. In any case, it’s a gem.”

    The newly discovered planet measures about 1.1 Earth radii, making it slightly larger than Earth, but researchers still think the alien world may be rocky like Earth. Researchers still aren’t sure what Kepler-186f’s atmosphere is made of, a key element that could help scientists understand if the planet is hospitable to life.

    “What we’ve learned, just over the past few years, is that there is a definite transition which occurs around about 1.5 Earth radii,” Quintana said in a statement. “What happens there is that for radii between 1.5 and 2 Earth radii, the planet becomes massive enough that it starts to accumulate a very thick hydrogen and helium atmosphere, so it starts to resemble the gas giants of our solar system rather than anything else that we see as terrestrial.”

    k
    This diagram shows the position of Kepler-186f in relation to Earth.
    Credit: NASA Ames/SETI Institute/JPL-CalTech

    The edge of habitability

    Kepler-186f actually lies at the edge of the Kepler-186 star’s habitable zone, meaning that liquid water on the planet’s surface could freeze, according to study co-author Stephen Kane of San Francisco State University.

    Because of its position in the outer part of the habitable zone, the planet’s larger size could actually help keep its water liquid, Kane said in a statement. Since it is slightly bigger than Earth, Kepler-186f could have a thicker atmosphere, which would insulate the planet and potentially keep its water in liquid form, Kane added.

    “It [Kepler-186f] goes around its star over 130 days, but because its star is a lower mass than our sun, the planet orbits slightly inner of where Mercury orbits in our own solar system,” Barclay said. “It’s on the cooler edge of the habitable zone. It’s still well within it, but it receives less energy than Earth receives. So, if you’re on this planet [Kepler-186f], the star would appear dimmer.”

    Exoplanet hunting in the future

    Kepler-186f could be too dim for follow-up studies that would probe the planet’s atmosphere. NASA’s James Webb Space Telescope Hubble’s successor, expected to launch to space in 2018 — is designed to image planets around relatively nearby stars; however, the Kepler-186 system might be too far off for the powerful telescope to investigate, Barclay said.

    NASA Webb Telescope

    NASA Hubble Telescope

    Scientists using the Kepler telescope discovered Kepler-186f using the transit method: When the planet moved across the face of its star from the telescope’s perspective, Kepler recorded a slight dip in the star’s brightness, allowing researchers to learn more about the planet itself. Kepler suffered a major malfunction last year and is no longer working in the same fashion, but scientists are still going through the spacecraft’s trove of data searching for new alien worlds.

    “I find it simply awesome that we live in a time when finding potentially habitable planets is common, and the method to find them is standardized,” MIT exoplanet hunter and astrophysicist Sara Seager, who is unaffiliated with the research, told Space.com via email.

    The new research was published online today (April 17) in the journal Science.

    See the full article here.

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  • richardmitnick 9:31 am on November 21, 2014 Permalink | Reply
    Tags: , , , , Exoplanets, ,   

    From Science Daily: “How to estimate the magnetic field of an exoplanet” 

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    [Similar material to an earlier post; but a different slant.]

    Science Daily

    November 20, 2014
    Source: Lomonosov Moscow State University

    Scientists developed a new method which allows to estimate the magnetic field of a distant exoplanet, i.e., a planet, which is located outside the Solar system and orbits a different star. Moreover, they managed to estimate the value of the magnetic moment of the planet HD 209458b.The group of scientists including one of the researchers of the Lomonosov Moscow State University (Russia) published their article in the Science magazine.

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    Size comparison of HD 209458 b with Jupiter.

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    Artist’s interpretation of Planet HD 209458b. Scientists have now estimated the value of the magnetic moment of the planet HD 209458b.
    Credit: NASA/ESA/CNRS/Alfred Vidal-Madjar

    In the two decades which passed since the discovery of the first planet outside the Solar system, astronomers have made a great progress in the study of these objects. While 20 years ago a big event was even the discovery of a new planet, nowadays astronomers are able to consider their moons, atmosphere and climate and other characteristics similar to the ones of the planets in the Solar system. One of the important properties of both solid and gaseous planets is their possible magnetic field and its magnitude. On Earth it protects all the living creatures from the dangerous cosmic rays and helps animals to navigate in space.

    Kristina Kislyakova of the Space Research Institute of the Austrian Academy of Sciences in Graz together with an international group of physicists for the first time ever was able to estimate the value of the magnetic moment and the shape of the magnetosphere of the exoplanet HD 209458b. Maxim Khodachenko, a researcher at the Department of Radiation and computational methods of the Skobeltsyn Institute of Nuclear Physics of the Lomonosov Moscow State University, is also one of the authors of the article. He also works at the Space Research Institute of the Austrian Academy of Sciences.

    Planet HD 209458b (Osiris) is a hot Jupiter, approximately one third larger and lighter than Jupiter. It is a hot gaseous giant orbiting very close to the host star HD 209458. HD 209458b accomplishes one revolution around the host star for only 3.5 Earth days. It has been known to astronomers for a long time and is relatively well studied. In particular, it is the first planet where the atmosphere was detected. Therefore, for many scientists it has become a model object for the development of their hypotheses.

    Scientists used the observations of the Hubble Space Telescope of the HD 209458b in the hydrogen Lyman-alpha line at the time of transit, when the planet crosses the stellar disc as seen from Earth. At first, the scientists studied the absorption of the star radiation by the atmosphere of the planet. Afterwards they were able to estimate the shape of the gas cloud surrounding the hot Jupiter, and, based on these results, the size and the configuration of the magnetosphere.

    NASA Hubble Telescope
    NASA/ESA Hubble

    “We modeled the formation of the cloud of hot hydrogen around the planet and showed that only one configuration, which corresponds to specific values of the magnetic moment and the parameters of the stellar wind, allowed us to reproduce the observations,” explained Kristina Kislyakova.

    To make the model more accurate, scientists accounted for many factors that define the interaction between the stellar wind and the atmosphere of the planet: so-called charge exchange between the stellar wind and the neutral atmospheric particles and their ionization, gravitational effects, pressure, radiation acceleration, and the spectral line broadening.

    At present, scientists believe that the size of the atomic hydrogen envelope is defined by the interaction between the gas outflows from the planet and the incoming stellar wind protons. Similarly to Earth, the interaction of the atmosphere with the stellar wind occurs above the magnetosphere. By knowing the parameters of an atomic hydrogen cloud, one can estimate the size of the magnetosphere by means of a specific model.

    Since direct measurements of the magnetic field of exoplanets are currently impossible, the indirect methods are broadly used, for example, using the radio observations. There exist a number of attempts to detect the radio emission from the planet HD 209458b. However, because of the large distances the attempts to detect the radio emission from exoplanets have yet been unsuccessful.

    “The planet’s magnetosphere was relatively small being only 2.9 planetary radii corresponding to a magnetic moment of only 10% of the magnetic moment of Jupiter,” explained Kislyakova, a graduate of the Lobachevsky State University of Nizhny Novgorod. According to her, it is consistent with the estimates of the effectiveness of the planetary dynamo for this planet.

    “This method can be used for every planet, including Earth-like planets, if there exist an extended high energetic hydrogen envelope around them,” summarized Maxim Khodachenko.

    Journal Reference:

    K. G. Kislyakova, M. Holmstrom, H. Lammer, P. Odert, M. L. Khodachenko. Magnetic moment and plasma environment of HD 209458b as determined from Ly observations. Science, 2014; 346 (6212): 981 DOI: 10.1126/science.1257829

    See the full article here.

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  • richardmitnick 11:46 am on November 20, 2014 Permalink | Reply
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    From WIRED: “War of the Worlds” 

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    Wired

    No Date posted
    Lee Billings

    Two teams of astronomers may have found the first earth-like planet in outer space. So who truly discovered Gliese 667C

    g
    Artist’s impression of Gliese 667 Cb with the Gliese 667 A/B binary in the background

    No one knows what the planet Gliese 667Cc looks like. We know that it is about 22 light-years from Earth, a journey of lifetimes upon lifetimes. But no one can say whether it is a world like ours, with oceans and life, cities and single-malt Scotch. Only a hint of a to-and-fro oscillation in the star it orbits, detectable by Earth’s most sensitive telescopes and spectrographs, lets astronomers say the planet exists at all. The planet is bigger than our world, perhaps made of rocks instead of gas, and within its star’s “habitable zone”—at a Goldilocks distance that ensures enough starlight to make liquid water possible but not so much as to nuke the planet clean.

    That’s enough to fill the scientists who hunt for worlds outside our own solar system—so-called exoplanets—with wonder. Gliese 667Cc is, if not a sibling to our world, at least a cousin out there amid the stars. No one knows if it is a place we humans could someday live, breathe, and watch triple sunsets. No one knows whether barely imagined natives are right now pointing their most sensitive and far-seeing technology at Earth, wondering the same things. Yet regardless, to be the person who found Gliese 667Cc is to be the person who changes the quest for life beyond our world, to be remembered as long as humans exist to remember—by the light of the sun or a distant, unknown star.

    Which is a problem. Because another thing no one knows about Gliese 667Cc is who should get credit for discovering it.

    Gliese 667Cc is at the center of an epic controversy in astronomy—a fight over the validity of data, the nature of scientific discovery, and the ever-important question of who got there first.

    In late 1995 Swiss astronomer Michel Mayor and his student Didier Queloz found 51 Pegasi b, the first known exoplanet orbiting a sunlike star. It was orbiting far too close to its sun to allow the formation of water, but the discovery made Mayor’s European team world famous anyway.

    Soon, though, they lost their lead in the planet-hunting race to a pair of American researchers, Geoff Marcy and Paul Butler. The two men had been looking for exoplanets for almost a decade; they bagged their first two worlds a couple of months after Mayor’s announcement.

    The two teams evolved into fiercely competitive dynasties, fighting to have the most—and most tantalizing—worlds to their names. Their rivalry was good for science; within a decade, each had found on the order of a hundred planets around a wide variety of stars. Soon the hunt narrowed to a bigger prize. The teams went searching for smaller, rocky planets they could crown “Earth-like.”

    w
    The Spectral fluctuations of a star with an exoplanet create a sine wave.

    Most planet hunters aren’t looking for exoplanets, per se. Those worlds are too small and dim to easily see. They’re looking instead for telltale shifts in the light of a star, “wobbles” in its spectral identity caused by the gravitational pull of an unseen orbiting exoplanet. When that force tugs a star toward Earth, the Doppler effect ever so slightly compresses the waves of light it emits, shifting them toward the blue end of the spectrum. When the star moves away from Earth, its waves of starlight stretch to reach us, shifting toward the red. You can’t see those shifts with the naked eye. Only a spectrograph can, and the more stable and precise it is, the smaller the wobbles—and planets—you can find.

    By late 2003 the European team had a very precise instrument, the [ESO] High Accuracy Radial velocity Planet Searcher, or Harps. Mounted to a 3.6-meter telescope on a mountaintop in Chile, Harps could detect wobbles of less than a meter per second. (Earth moves the sun just a tenth that amount.) The Americans had to make do with an older instrument called the [Keck]High Resolution Echelle Spectrometer, or Hires—less precise but paired with a more powerful telescope.

    ESO HARPS
    ESO HARPS at the ESO La Silla 3.6m telescope

    Keck HIRES
    HIRES at Keck Observatory

    As the two teams continued to fight for preeminence, trouble was brewing among the Americans. Marcy, a natural showman as well as a brilliant scientist, regularly appeared on magazine covers, newspaper front pages, and even David Letterman’s late-night show. His far more taciturn partner, Butler, preferred the gritty tasks of refining data pipelines and calibration techniques. Having devoted years of their lives to the planet-hunting cause, Butler and another member of the team, Marcy’s PhD adviser, Steve Vogt (the mastermind behind Hires), began to feel marginalized and diminished by Marcy’s growing fame. The relationships hit a low in 2005, when Marcy split a $1 million award with their archrival Mayor. Marcy credited Butler and Vogt in his acceptance speech and donated most of the money to his home institutions, the University of California and San Francisco State University, but the damage was done. Two years later, the relationship disintegrated. Butler and Vogt formed their own splinter group; Butler and Marcy have barely spoken since.

    It was a risky move. Harps and Hires remained the best planet-hunting spectrographs available, and Butler and Vogt now lacked easy access to fresh data from either one. The American dynasty was shattered, and Marcy was forced to find new collaborators. Meanwhile, the ever-expanding European team continued to wring planets from Harps even though Mayor had formally retired in 2007. The search for Earth 2.0, long seen as a struggle between two teams, became a more crowded and open contest.

    Then a seeming breakthrough: In the spring of 2007, the Europeans announced that they’d spotted a potentially habitable world, Gliese 581d.1 It was a blockbuster—a “super-Earth”—on the outer edge of the habitable zone, eight times more massive than our own world.

    Three years later, in 2010, Butler and Vogt scored their own big find around the same star—Gliese 581g. It was smack in the center of the habitable zone and only three or four times the bulk of Earth, so idyllic-seeming that Vogt poetically called it Zarmina’s World, after his wife, and said he thought the chances for life there were “100 percent.” Butler beamed too, in his own subdued way, saying “the planet is the right distance from the star to have water and the right mass to hold an atmosphere.” They had beaten Marcy, laid some claim to the first potentially Earth-like world, and bested their European competitors.

    But to a chorus of skeptics, Zarmina’s World seemed too good to be true. The European group said the signals the Americans had seen were too weak to be taken seriously. The fight was getting ugly; entire worlds were at stake.

    Plotted on a computer screen, a stellar wobble caused by a single planet looks like a sine wave, though real measurements are rarely so clear. A centimeters-per-second wobble in a million-kilometer-wide ball of seething, roiling plasma isn’t exactly a bright beacon across light-years. Spotting it takes hundreds to thousands of observations, spanning years, and even then it registers as a fractional offset of a single pixel in a detector. Sometimes a signal in one state-of-the-art spectrograph will fail to manifest in another. Researchers can chase promising blips for years, only to see their planetary dreams evaporate. Finding a stellar wobble caused by a habitable world requires a volatile mix of scientific acumen and slow-simmering personal obsession.

    A Spanish astronomer named Guillem Anglada-Escudé certainly meets that description. Now a lecturer at Queen Mary University in London, he began working with the American breakaways Butler (a friend and collaborator) and Vogt not long after they announced Gliese 581g.

    Today, Anglada-Escudé’s name is on the books next to between 20 and 30 exoplanets, many found by scraping public archives in search of weak, borderline wobbles. The European Southern Observatory, which funds Harps, mandates that the spectrograph’s overlords release its data after a proprietary period of a year or two. That gives other researchers access to high-quality observations and potential discoveries that the Harps team might have missed. Scavenging scraps from the European table, it turns out, can be almost as worthwhile as being invited to the meal.

    In the summer of 2011, Anglada-Escudé was a 32-year-old postdoc at the end of a fellowship, looking for a steady research position in academia. With Butler’s help he had developed alternative analytic techniques that he used to scour public Harps data. In fact, Anglada-Escudé argued that his approach treated planetary data sets more thoroughly and efficiently, harvesting more significant signals from the noise.

    One late night that August, he picked a new target: nearly 150 observations of a star called Gliese 667C2 taken by the Harps team between 2004 and 2008. He sat before his laptop in a darkened room, waiting impatiently as his custom software slowly crunched through possible physically stable configurations of planets within the data.

    The first wobble to appear suggested a world in a seven-day orbit—the faster the orbit, the closer to the star the planet must be. A weeklong year is about enough time to get roasted to an inhospitable cinder—and anyway the Harps team had announced that one in 2009, as the planet Gliese 667Cb. But Anglada-Escudé spied what looked suspiciously like structure in the residuals of the stellar sine wave snaking across his screen. He ran his software again and another signal emerged, a strong oscillation with a 91-day period—possibly a planet, possibly a pulsation related to the estimated 105-day rotation period of the star itself.

    1 Astronomer Wilhelm Gliese cataloged hundreds of stars in the 1950s. The lowercase letter marks the order in which astronomers discovered the planets orbiting a star.

    2 The capital C indicates a trinary system, with A and B stars.

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