A team of astronomers announced they have discovered the smallest and potentially most Earth-like extrasolar planet yet. Five times as massive as Earth, it orbits a relatively cool star at a distance that would provide earthly temperatures as well, signaling the possibility of liquid water.
“The separation between the planet and its star is just right for having liquid water at its surface,” says astronomer and team spokesperson Stephane Udry of the Observatory of Geneva in Versoix, Switzerland. “That’s why we are a bit excited.”
But researchers do not yet know if the planet contains water, if it is truly rocky like Earth, which might make it hospitable to life as we know it, or whether it is blanketed by a thick atmosphere. “What we have,” Udry says, “is the minimum mass of the planet and its separation” from its star.
The researchers say they detected the presence of two new extrasolar planets (exoplanets) around a red dwarf star, Gliese 581, 20.5 light-years away in the constellation Libra, based on slight motions of the star. Their discovery brings the total number of planets orbiting Gliese 581 to three; two years ago they made the initial finding of a planet there.