Extrasolar Carbon Dioxide

Giant planet HD 189733b is about to disappear behind its star. Credit: ESA, NASA, M. Kornmesser (ESA/Hubble), and STScI

For the first time, scientists have discovered carbon dioxide in the atmosphere of an extrasolar planet, the increasingly well-known HD 189733b.  

The planet has become well-known for extrasolar "firsts."  In February, scientists announced the first-ever extrasolar discovery of methane in the planet's atmosphere -- the first time an organic molecule had been found in the atmosphere of an extrasolar planet -- and in July 2007 scientists made the first-ever extrasolar discovery of water in the same planet's atmosphere.  

According to Planet Quest.com:

NASA's Hubble Space Telescope has discovered carbon dioxide in the atmosphere of a planet orbiting another star. This breakthrough is an important step toward finding chemical biotracers of extraterrestrial life. 

The Jupiter-sized planet, called HD 189733b, is too hot for life. But the Hubble observations are a proof-of-concept demonstration that the basic chemistry for life can be measured on planets orbiting other stars. Organic compounds also can be a by-product of life processes, and their detection on an Earthlike planet someday may provide the first evidence of life beyond our planet. 

More information available at NASA and Astrobiology Magazine.