Journal of Geophysical Research: Planets The relative influence of H 2 O and CO 2 on the primitive surface conditions and evolution of rocky planets
Journal of Geophysical Research: Planets The relative influence of H 2 O and CO 2 on the primitive surface conditions and evolution of rocky planets
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地球物理研究杂志：行星 H 2 O 和 CO 2 对岩石行星原始表面条件和演化的相对影响
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通讯作者：
C. Poirot
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作者：
P. Dreden;J. Gonzalès;C. Poirot
挥发性成分如何影响类地行星的原始表面条件，从而影响它们未来的地球动力学演变是一个需要回答的重要问题。我们模拟了一维岩浆海（MO）与它的排气大气相互作用下的长期对流冷却过程。用灰色近似法或k相关法计算大气中的热传递。我们改变初始CO 2和H 2 O的含量(分别从0。1 × 10−2 ~ 14 × 10−2 wt %和0.03 ~ 1.4倍地球洋流质量)和太阳距离- 0.63 ~ 1.30 AU。在第一个快速冷却阶段，MO发生有效冷却和脱气，产生大气，随后是第二个准稳态，热流平衡由太阳通量主导。当地幔热通量与吸收的太阳通量相比变得可以忽略不计时，到达快速冷却阶段（ERCS）的结束。在ERCS得到的表面条件，包括水海洋的形成，强烈地依赖于初始挥发性含量和太阳距离D。对于“临界距离”D > dc，挥发分含量控制冷凝水，导出了冷凝水极限的新标度规律。虽然今天的金星由于高反照率而位于d.c.以外，但它的高co2 / h2o比率阻止了任何水海洋的形成。根据其云层的形成时间和反照率，仅0.3个地球海洋质量就可能足以在其上形成一个水海洋
How the volatile content influences the primordial surface conditions of terrestrial planets and, thus, their future geodynamic evolution is an important question to answer. We simulate the secular convective cooling of a 1-D magma ocean (MO) in interaction with its outgassed atmosphere. The heat transfer in the atmosphere is computed either using the grey approximation or using a k -correlated method. We vary the initial CO 2 and H 2 O contents (respectively from 0 . 1 × 10 − 2 to 14 × 10 − 2 wt % and from 0.03 to 1.4 times the Earth Ocean current mass) and the solar distance—from 0.63 to 1.30 AU. A first rapid cooling stage, where efficient MO cooling and degassing take place, producing the atmosphere, is followed by a second quasi steady state where the heat flux balance is dominated by the solar flux. The end of the rapid cooling stage (ERCS) is reached when the mantle heat flux becomes negligible compared to the absorbed solar flux. The resulting surface conditions at ERCS, including water ocean’s formation, strongly depend both on the initial volatile content and solar distance D . For D > D C , the “critical distance,” the volatile content controls water condensation and a new scaling law is derived for the water condensation limit. Although today’s Venus is located beyond D C due to its high albedo, its high CO 2 /H 2 O ratio prevents any water ocean formation. Depending on the formation time of its cloud cover and resulting albedo, only 0.3 Earth ocean mass might be sufficient to form a water ocean on