Dissipation of the primordial terrestrial atmosphere due to irradiation of the solar EUV
Dissipation of the primordial terrestrial atmosphere due to irradiation of the solar EUV
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太阳 EUV 照射导致原始陆地大气的耗散
DOI：
10.1143/ptp.64.1968
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发表时间：
1980
影响因子：
--
通讯作者：
C. Hayashi
中科院分区：
文献类型：
--
作者：
M. Sekiya;K. Nakazawa;C. Hayashi
通过对稳定的球对称氢分子和氦原子流出的数值流体动力学方程进行积分，研究了原始地球大气因太阳辐射加热而逸出的问题。作为热源，我们考虑了(1)预计在金牛座T阶段非常强烈的太阳EUV辐射，(2)太阳可见光和(3)吸积星子释放的引力能。忽略了太阳风的影响，但估计了这种忽略的条件。结果表明，在地球历史早期就存在的原始大气在5 × 108 y的周期内耗竭，这是现在地球大气起源所施加的上限，只要太阳EUV通量大于2倍。
The escape of a primordial Earth's atmosphere due to heating by solar radiation is studied by integrating numerically hydrodynamic equations for steady and spherically symmetric outflow of hydrogen molecules and helium atoms. As heating sources, we take account of (1) the solar EUV radiation which is expected to be very strong during the T Tauri stage, (2) the solar visible light and (3) the release of gravitational energy of accreting planetesimals. The effect of solar wind is neglected but the condition of this neglect is estimated. The results show that the primordial atmosphere, having existed in the early stage of the Earth's history, is dissipated within a period of 5 X 108 y, which is the upper limit imposed from the origin of the present terrestrial atmosphere, as far as the solar EUV flux is more than 2 >< 10 2 times as large as the present one.