The first "Earth-class" extrasolar planet has been discovered by a team of scientists led by former DTM postdoctoral fellow Eugenio Rivera (now at UC, Santa Cruz) along with DTM staff member Paul Butler, Geoffrey Marcy (UC Berkeley), Jack Lissauer (NASA Ames), Steve Vogt (UC Santa Cruz), Debra Fischer (San Francisco State University), Timothy Brown (High Altitude Observatory/National Center for Atmospheric Research), and Gregory Laughlin (UC Santa Cruz). Their discovery was announced June 13 at a National Science Foundation press conference in Arlington, VA. Archived webcasts of the conference can be viewed here.

The host star to this new planet, GL 876, is one of the nearest stars in the sky, only 15 light years away from Earth. With one-third of the Sun's mass, GL 876 is classified as a red dwarf, along with 70% of all stars. The newly discovered planet orbits GL 876 every 2 days at a distance of only 2 million miles (2% of the Earth-sun distance). This close proximity heats the planet's surface to an oven-like temperature. In addition, the new planet is between 6 and 8 Earth-masses, making it too small to be a gas giant like Jupiter and Saturn or one of the ice giants Uranus and Neptune, which are twice as massive. This small mass and close-in orbit have led the team to speculate that the planet is a made up of rock and metal, similar to the inner planets in our solar system, including Earth.

The team behind the discovery now seeks additional rocky Earth-like planets at orbital distances consistent with liquid water around nearby red dwarf stars. More information about this discovery can be found at the group’s website.