U.S. astronomers say they have for the first time identified a planet circling two suns.
The U.S. space agency NASA Thursday introduced a planet they are calling Kepler-16b, for the Kepler telescope used to sight the celestial body. Kepler-16b is inhospitable and cold — unlikely to be home sweet home for any extraterrestrials.
But project chief William Borucki says the discovery proves that scientists do not have to limit their search for potentially-life-harboring planets to star systems like our own.
Borucki says until now, astronomers had only confirmed the existence of planet systems like ours that circle a single star. But he says most stars in our galaxy are not solitary objects; most are paired in binary systems.
Borucki says scientists had long theorized they would also find planets in orbit around double-star pairs, but Kepler-16b is the first time they could prove it.
Kepler-16b is 200 light years from Earth, and it orbits two stars that also orbit each other. From Earth, the two stars seem to eclipse each other — in other words, the star system looks dimmer when the stars are blocking each other from our sight. But scientists noticed the star system sometimes dimmed even when the stars were not aligned, indicated there was a third object in play. Because the intervals of this additional dimming were irregular, scientists were able to show the stars were in different positions each time the third body passed — showing it was circling not one, but both stars.