Science2014-06-10 5:38 PM

一颗遥远的很像地球的行星 An Earth-Sized Planet in the Habitable Zone of a Cool Star

论文摘要 

据一项新的研究报告,一直在搜索天空的科学家们发现了一颗和地球大小差不多的行星,且在理论上这颗行星可以容纳液态水。这对于发现环绕我们太阳以外的恒星运转的可居住行星而言是一个里程碑。太阳是一个炽热光亮的质块,它距我们9300万英里之外;这一距离远到足以不会让我们的海洋蒸发,但又近到足以将水维持在液态,而这是我们所知的生命所需要的状态。换言之,相对于这一灿烂的恒星,地球位于其可居住的区域。近些年来,一直通过用NASA的开普勒太空船来寻找环绕太阳样恒星做轨道运行的系外行星的科学家们已经取得了进展,他们发现了包括某些位于可居住区域内的系外行星。然而,这些系外行星中没有一个与地球的大小相近。如今,在用开普勒太空船对太阳系进行多年的监测之后,elisa Quintana及其同事报告说,他们探测到5颗行星,它们环绕着一颗叫做Kepler-186的恒星做轨道运行;至关重要的是,它们中最外围的行星Kepler-186f似乎处于Kepler-186的可居住区域,且它与地球的大小接近(只比地球大10%)。据这些研究人员披露,该行星接受的是适量的恒星辐射——且辐射量不过多也不过少——因此,如果该行星上有水存在,它理论上能够在该行星的表面以液态存在。

Abstract 

The quest for Earth-like planets is a major focus of current exoplanet research. Although planets that are Earth-sized and smaller have been detected, these planets reside in orbits that are too close to their host star to allow liquid water on their surfaces. We present the detection of Kepler-186f, a 1.11 ± 0.14 Earth-radius planet that is the outermost of five planets, all roughly Earth-sized, that transit a 0.47 ± 0.05 solar-radius star. The intensity and spectrum of the star’s radiation place Kepler-186f in the stellar habitable zone, implying that if Kepler-186f has an Earth-like atmosphere and water at its surface, then some of this water is likely to be in liquid form.

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