Carbon dioxide detected for the first time on extrasolar planet: HD 189733b

Monday, November 24, 2008

Wow, the extrasolar planet news just keeps coming. At this exponential growth we're pretty much at the point where you could dedicate a whole blog just to extrasolar planets and not run out of things to write about daily. This discovery is around another planet that isn't habitable so the discovery has nothing to do with the possibility of life (as we know it that is) on that planet, but it's still the first time we've discovered CO2 on a planet in another solar system which is what makes it newsworthy.

Carbon dioxide, a potential fingerprint of life, has been discovered for the first time in the atmosphere of a planet orbiting another star.

However, the planet, HD 189733b, is too hot to be habitable.

But the discovery nonetheless has scientists excited, because carbon dioxide is one of four chemicals that life can generate, so being able to detect it shows that astronomers have the ability to find the signs of life on other worlds.

"This is the first detection of carbon dioxide in the atmosphere of an extrasolar planet, which means that three of the Big Four biomarkers for habitable/inhabited worlds have now been seen: water, methane, and now carbon dioxide," explained Alan Boss, a planet-formation theorist at the Carnegie Institution of Washington who was not involved in the finding. "The only one that has not yet been detected is oxygen/ozone."

Boss told that the detections provide "proof of concept" for what astronomers would search for in looking at an Earth-like world. The detection of carbon dioxide, Boss said, was made with a low degree of resolving power, the sort that could be provided by NASA's planned Terrestrial Planet Finder.

HD 189733b is about 65 light-years away. It is a giant, gaseous world known as a "hot Jupiter" because it orbits very close to its host star.


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