Astronomers detect a second planet around Proxima Centauri

摘要

The planet orbiting the star closest to the sun may have a neighbor. Proxima Centauri, a star 4.2 light-years from Earth, hosts one potentially habitable planet, Proxima b, that's a bit more massive than Earth (SN: 9/27/16, p. 6). Now, astronomers see hints of a much larger planet that is farther from the star. If it exists, Proxima c appears to be at least 5.8 times as massive as Earth and orbits its star about once every five Earth years, researchers report January 15 in Science Advances. Given its distance from Proxima Centauri, the planet is too cold to have liquid water, a test for habitability.