Astronomy: Exoplanets on the cheap

[jakeXT]

The search for planets outside our Solar System will always be pricey. But creative solutions are proving that it no longer has to break the bank.

The exoplanet search itself has been wildly successful, but not so the searchers' quest for multibillion-dollar follow-up missions. Hopes for ambitious spacecraft such as a Space Interferometry Mission or Terrestrial Planet Finder have been dashed as missions have been cancelled or postponed owing to a combination of sluggish economic growth, deep cuts to space-science funding and programme difficulties with NASA's James Webb Space Telescope (JWST).

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The first, and so far most successful, search for potentially habitable planets transiting M-dwarfs is the MEarth Project (pronounced 'mirth'): a cluster of eight 0.4-metre robotic telescopes at the Whipple Observatory on Mount Hopkins in Arizona. Unlike all previous transit surveys, which stare at a fixed patch of sky rich with stars, MEarth targets 2,000 nearby M-dwarfs; only if one of these displays a candidate transit will all telescopes observe it at once. The project is headed by David Charbonneau, an astronomer at Harvard University in Cambridge, Massachusetts, and was designed mainly by Philip Nutzman, now a postdoctoral researcher in astronomy at the University of California, Santa Cruz. MEarth announced the discovery of its first transiting planet in 2009 — a world dubbed GJ 1214 b, after the M-dwarf star it orbits some 13 parsecs from Earth3. The planet is too large and hot to harbour life as we know it, but was found in only the first six months of MEarth's proposed three-year running time, and so far remains the most easily studied Earth-like exoplanet known. A spectroscopic study of GJ 1214 b, undertaken last year at the European Southern Observatory (ESO) in La Silla, Chile, showed that the planet's upper atmosphere is either very hazy or is composed of water vapour4.

"MEarth shows that for a relatively modest investment of US$1 million or $2 million, you can put together a ground-based survey capable of finding habitable-zone super-Earths," says Charbonneau, referring to rocky planets that are larger than Earth and orbit their stars at a distance at which water can exist as a liquid. "The answer to the question being asked is certainly worth a lot more than that."

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http://www.nature.com/news/2011/110202/full/470027a.html
or as pdf
http://www.nature.com/news/2011/110202/pdf/470027a.pdf


I didn't know they already found water, findig oxygen and water on a newly discovered Earth sized planet in the habitable zone would be a great thing.

[jakeXT]

1. A Boost for Exoplanet Atmosphere Studies

What JPL’s Mark Swain calls ‘an absolutely brilliant way to characterize super-Earths’ has emerged from work performed with a small NASA infrared telescope, one that has allowed scientists to identify an organic molecule in the atmosphere of a distant gas giant. HD 189733b is an old friend by now, the subject of intensive studies with space-based telescopes that have revealed water vapor, methane and carbon dioxide in its atmosphere. In the new work, Swain’s team made a spectrographic detection of carbon dioxide and methane using a ground-based instrument and a new method to remove the effects of tracking errors and the variability induced by changes in the Earth’s atmosphere.



http://www.centauri-dreams.org/?p=11263