Harvard Announces "first Nearby Transiting Super-Earth Exoplanet"

The "first nearby transiting super-Earth exoplanet" - a major scientific discovery - has been discovered by David Charbonneau and his team at Harvard University, and a paper announcing the find is being published today in Nature. The planet, labeled GJ 1214b, orbits a star that puts out far less light than the sun - only about .003 as much. It was discovered by the MEarth team led by David Charbonneau of the Harvard-Smithsonian Center for Astrophysics. Charbonneau is also the Cabot Professor of Astronomy at Harvard.

While the discovery is a major first, it is qualified by the estimated surface temperature of the planet: 392 Fahrenheit. Water boils at 212 degrees, so think like a lobster if you're planning on visiting. Of course, the forty light-year distance to the planet puts it far beyond reach of humans. Still, the discovery is a real first in the sense that it is the first extrasolar planet that has Earthlike features at such a relatively short distance and at temperatures lower than other known exoplanets. The Earthlike features include water, a surface that is at least partly rocky, and an atmosphere.

GJ 1214b is has a radius that is about 2.7 that of Earth, and it orbits the parent star every 38 hours. Its mass is 6.6 times that of Earth.

As of November 2, 2009, there were only about 403 known extrasolar planets according to the Jet Propulsion Lab. The first extrasolar planet was discovered in 1995 by Mayor and Queloz and immediately confirmed by Geoffrey W. Marcy, a professor from San Francisco State University.

The MEarth website defines its mission: "The MEarth Project is a survey to photometrically monitor 2000 nearby, small stars (called M dwarfs), looking for periodic dips in light, due to the presence of habitable super-Earth exoplanets transiting in front of the star." Using the transit method, an astronomer spots a planet by detecting a slight decrease in light as the planet passes in front of the parent star. The orbit of such an object planet causes it to pass in front of the star; it then passes behind the star. "Mearth" is apparently taken from the words "M Dwarf" and "Earth". Charbonneau co-authored a recent paper about the project with Philip Nutzman.

Zachory Berta, a graduate student, first found signs of the planet in astronomical data. According to Berta, "It is much smaller, cooler, and more Earthlike than any other known exoplanet."

Charonneau made no comment on the delay from NASA in providing additional data from the Hubble Telescope, which he said should be able to provide more data on the planet.

Sources:

Website of Professor David Charbonneua, Harvard University

Mearth Project website

Press Release, Harvard-Smithsonian Center for Astrophysics