National Aeronautics and Space Administration (NASA) announced Tuesday that a planet of rock, orbiting extremely close to its host star, has been identified as the smallest ever discovered outside the solar system. It is also the first rocky, or Earth-like planet discovered by Kepler.

美国宇航局周二宣称已发现目前系外最小、且与主星距离极近的石性行星。这也是美国宇航局空基望远镜开普勒所发现的第一颗石性行星，也称类地行星.


Dubbed Kepler-10b, the exoplanet is about 560 light years from Earth. And with 1.4 times the size of Earth, Kepler-10b is more than 20 times closer to its star than Mercury is to the sun, and whips around the star once every 0.84 days.

该系外行星名为“开普勒-10b”，距离地球约有560光年。其大小是地球的1.4倍，距其主星的距离却比水星与太阳之间的距离小了20倍之多，而公转周期也缩短至0.84天。


This makes it impossible for life to exist on the exoplanet, according to NASA. It's so hot that boiled iron and silicates are flowing into the stellar wind, much like a comet's tail.

美国宇航局称，这种近距离不可能让“开普勒-10b”上有生命迹象。该星球表面的热度足以融化铁和硅酸盐，被熔物质随后流入恒星风，宛若彗星尾巴。


Still, the discovery has scientists optimistic about what else Kepler might be able to reveal. “Although this planet is not in the habitable zone, the exciting find showcases the kinds of discoveries made possible by the mission,” said Kepler program scientist Douglas Hudgins.

即使如此，该发现还是让科学家为之一振，他们期待开普勒能有更多新发现。“尽管这颗行星不在可居住带，该发现还是让人兴奋无比的，因为它表明了更多类似发现的可能性，”开普勒项目科学家道格拉斯 哈金斯说道。