Bringing the search for another Earth about as close as it will ever get, a team of European astronomers was scheduled to announce on Wednesday that it had found a planet the same mass as Earth’s in Alpha Centauri, a triple star system that is the Sun’s closest neighbor, only 4.4 light-years away.
The planet is the lightest one ever found orbiting another star and — in the words of its discoverer, Xavier Dumusque, a graduate student at the Geneva Observatory — “it will surely be the closest one ever.”
It is presumably a rocky ball like our own, but it is not habitable. It circles Alpha Centauri B, a reddish orb about half as luminous as the Sun, every three days at a distance of only about four million miles, resulting in hellish surface temperatures of 1,200 degrees.
So this is not “Earth 2.0.” Yet.
Astronomers said the discovery raised the possibility that there were habitable Earthlike planets right next door and that methods and instruments were now precise enough to detect them.
“Very small planets are not rare,” said Mr. Dumusque, who is the lead author of a paper being published on Wednesday in Nature. “When you find one small planet, you find others.” He and his colleagues discussed the results on Tuesday in a news conference hosted by the European Southern Observatory in Garching, Germany.
Astronomers were electrified by the news of the planet, but also cautioned that it needed confirmation by other astronomers, not an easy task.
Debra Fischer, a Yale astronomer who has been searching for planets in that same system for years, said: “The discovery that our nearest neighbor has rocky planets is the story of the decade. I’d bet $100 that there are other planets that are there as well.”
This is a major discovery. There could be another planet in that system that is further away from Alpha Centauri B located in the "Goldilocks" habitable zone, that would be more difficult to dectect. To read more, click here.