Existence of Habitable Exoplanet Questioned

Ls_GJ581g_FNLa Ron Cowen in Science News:

In late September, an experienced group of U.S. astronomers made headlines with news of the first extrasolar planet likely to be hospitable to life. The planet lies at a distance from its parent star at which water could be liquid (SN: 10/23/10, p. 5).

But a Swiss team of veteran planet hunters has now cast some doubt on that finding. On October 11, Francesco Pepe of the Geneva Observatory in Sauverny, Switzerland, announced at an extrasolar planet meeting in Torino, Italy, that a combination of old and new data acquired by his team shows no sign of the planet, dubbed Gliese 581g.

“If a signal corresponding to the announced Gliese 581g planet was present in our data,” Pepe says, “we should have been able to detect it.”

Other astronomers say that only time, and more studies, will tell if the first exoplanet in the habitable zone has truly been found or not. “I don't know if we should be in such a hurry to say one way or the other,” says MIT astronomer Sara Seager. “We will have consensus at some point; I don't think we need to vote right now.”