Oh, man... [?][?][?][?] Thank you, Brent. The stuff of dreams.
On Tue, Jun 15, 2010 at 10:53 PM, brent wodehouse < brent_wodeho...@thefence.us> wrote: > > > > http://www.sciencenews.org/view/generic/id/60302/title/Kepler_craft_reports_apparent_planetary_bonanza > > Kepler craft reports apparent planetary bonanza > > Space telescope finds evidence of planets around hundreds of stars > > By Ron Cowen > > Surveying thousands of stars for telltale twinkles that signal the passage > of an orbiting planet, NASA’s Kepler spacecraft has discovered a whopping > 706 candidate planets beyond the solar system. If confirmed, that > motherlode would boost the number of known extrasolar planets, now > estimated at 460, to well over a thousand. > > The trove, announced June 15, includes evidence of five stars that have > full-fledged planetary systems. These exoplanet systems, if verified, > would be the first known in which each planet creates a minieclipse as it > transits, or passes in front, of its parent star. The amount of dimming > and the duration of a transit offer information about planets, including > their size, that cannot be gleaned by less direct methods of detection. > > A team including Kepler lead scientist William Borucki of NASA’s Ames > Research Center in Moffett Field, Calif., has posted the findings online > (at lanl.arxiv.org/abs/1006.2799 and at lanl.arxiv.org/abs/1006.2763) at > arXiv.org. The discoveries were made by analyzing Kepler’s first few > months of data, recorded in the spring of 2009 when the telescope examined > 156,000 stars. > > “This is a massively historic discovery,” says study coauthor Sara Seager, > a theorist at MIT. “This is showing how the Kepler mission will > revolutionize exoplanets and change the way we do exoplanet science.” > > The newly reported findings don’t include details about the most > interesting 400 of the 706 candidate planets, which orbit the brightest > stars Kepler has surveyed. These cases may offer the most promise for > finding planets with masses close to Earth‘s own. Information on these 400 > planets won’t be made public until next February. > > Although the five planetary systems still have to be verified, “they show > that Kepler will find dozens — and likely over a hundred — stars having > multiple planets that all transit in front of their host star,” says > veteran planet hunter and study coauthor Geoffrey Marcy of the University > of California, Berkeley. “Apparently, stars commonly house multiple > planets.” > > One candidate system consists of three orbs, while the other four contain > two. The orbiting objects range in size from twice Earth’s diameter to > slightly larger than that of Jupiter. They reside relatively close to > their stars, at distances ranging from roughly one-quarter to one-half > Mercury’s average separation from the sun. They are not yet confirmed > planets, however, because their masses have yet to be determined. > > Astronomers are already attempting to measure those masses, using > ground-based telescopes to discern the tiny wobble induced in the motion > of a parent star due to the tug of orbiting bodies. > > “We're using the Keck telescope [atop Hawaii’s Mauna Kea] 20 nights per > year just to follow up the Kepler planets,” Marcy says. > > Because these stars are dim and the expected wobble signal weak, > researchers may have to weigh the bodies using another method — variations > in the timing and duration of transits due to the gravitational interplay > among the planets in each system, says study coauthor Jason Steffen of the > Fermi National Accelerator Laboratory in Batavia, Ill. > > Even though the masses of the candidate planets remain unknown, the team > says it has already ruled out that the bodies are companion stars that > might be mimicking the minieclipses generated by transiting planets. It > would be particularly unlikely that a companion star could create the > pattern of eclipses seen in the candidate multiple planet systems, notes > Steffen. The main confounding source that the team hasn’t entirely > excluded would be a planet orbiting a neighboring star. > > Once the masses of the candidates are measured and combined with their > diameters from the transit observations, researchers can determine the > average densities of the bodies. > > “From those densities, we can distinguish rocky planets from gas giants > and water worlds,” says Marcy. “Kepler is opening a future for planet > hunting in which the orbits, masses, densities and architectures of full > planetary systems will be captured as a quantitative family portrait.” > > The findings may also bode well for finding systems similar to the Earth’s > solar system and for hunting habitable planets, comments Alan Boss of the > Carnegie Institution for Science in Washington, D.C., who is not a member > of the Kepler team. > > “The fact that multiple transiting planets are seen means that they must > all orbit more or less in the same plane, like our solar system,” he says. > In contrast, some recently identified planets don’t all lie in the same > plane (SN Online: 5/14/10 > [ > http://www.sciencenews.org/view/generic/id/59211/title/Planets_in_nearby_system_are_off-kilter%2C_measurements_show > ]) > and have probably been thrown around by gravitational interactions with > other planets in the system. More sedate systems might be more likely to > support life. > > > -- "If all the world's a stage and we are merely players, who the bloody hell wrote the script?" -- Charles E Grant http://www.youtube.com/watch?v=fQUxw9aUVik
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