The planet, found by astronomers at the University of California, Santa Cruz, and the Carnegie Institution of Washington, is orbiting in the middle of the “habitable zone” of the red dwarf star Gliese 581, which means it could have water on its surface.
Liquid water and an atmosphere are necessary for a planet to possibly sustain life, even it it might not be a great place to live, the scientists said.
The scientists determined that the planet, which they have called Gliese 581g, has a mass three to four times that of Earth and an orbital period of just under 37 days. Its mass indicates that it is probably a rocky planet and has enough gravity to hold on to an atmosphere, according to Steven Vogt, professor of astronomy and astrophysics at the University of California, Santa Cruz, and one of the leaders of the team that discovered the planet. If Gliese 581g has a rocky composition similar to Earth’s, its diameter would be about 1.2 to 1.4 times that of the Earth.
The surface gravity would be about the same or slightly higher than Earth’s, so that a person could easily walk upright on the planet. Gliese 581g was discovered by scientists working on the Lick-Carnegie Exoplanet Survey, during 11 years of observing the red dwarf star Gliese 581.
AFP