Constraints on the mass of a habitable planet with water of nebular origin
Constraints on the mass of a habitable planet with water of nebular origin
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DOI：
10.1086/505780
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发表时间：
2006-09-01
影响因子：
4.9
通讯作者：
Genda, Hidenori
中科院分区：
文献类型：
--
作者：
Ikoma, Masahiro;Genda, Hidenori
从天体生物学的角度来看，人们特别关注太阳系外系统中存在可居住行星的可能性。这项研究的目的是限制类地行星可以获得水的质量的可能范围。我们专注于水的生产过程中，通过氧化的大气氢-星云气体已被引力吸引-在行星表面的氧化物。为了在行星上生产水，需要足够的氢和足够高的温度来融化行星表面。我们模拟了与原行星状星云相连的大气结构，得到了大范围的热通量、不透明度和星云气体密度。我们已经发现，对于一个地球质量的行星来说，这两个要求在很宽的参数范围内都得到了满足。我们还发现，小于或接近0.3M（E）（其中M-E是地球的质量）的行星的表面温度低于硅酸盐的熔化温度（类似于1500 K）。另一方面，超过几个ME的行星通过星云气体的失控吸积而成为气体巨星。
From an astrobiological point of view, special attention has been paid to the probability of habitable planets in extrasolar systems. The purpose of this study is to constrain a possible range of the mass of a terrestrial planet that can get water. We focus on the process of water production through oxidation of atmospheric hydrogen - the nebular gas having been attracted gravitationally - by oxides available at the planetary surface. For the water production to work well on a planet, a sufficient amount of hydrogen and a temperature high enough to melt the planetary surface are needed. We have simulated the structure of the atmosphere that connects with the protoplanetary nebula for wide ranges of the heat flux, the opacity, and the density of the nebular gas. We have found that both requirements are fulfilled for an Earth- mass planet for wide ranges of the parameters. We have also found that the surface temperature of planets of less than or similar to 0.3M(E) (where M-E is Earth's mass) is lower than the melting temperature of silicate (similar to 1500 K). On the other hand, a planet of more than several ME becomes a gas giant through runaway accretion of the nebular gas.