Stars With Multiple Planets Are Common

Planets like company. No less than one in three of all planets around other stars found by NASA's Kepler space telescope are in multiple-planet systems. What's more, the sheer number of those systems suggests that they are more tranquil places than our own solar system, say astronomers working with the telescope.

Since it was launched just over 2 years ago, Kepler has found 116 systems with two planets, 45 with three, eight with four, one with five, and one with six planets, astronomer David Latham of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, reported here today at the meeting of the American Astronomical Society. That's a total of 171 multiple-planet systems. "We thought we might see a few multiplanet systems," Latham says. "Instead, we found lots of them."…

Also see Astrobiology Magazine.