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arXiv 1606.03030astro-ph.EP
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由于有限的CO $_2$放气率而导致的宜居带尺寸减小的分析研究

Analytical investigation of the decrease in the size of the habitable zone due to limited CO$_2$ outgassing rate

Dorian S. Abbot

摘要:

宜居带的概念很重要,因为它集中了对地外生命的科学探索,并有助于规划未来的望远镜。最近的研究表明,如果CO $_2$的释气速率不足以维持高的CO $_2$分压,防止硅酸盐风化作用的去除,那么靠近宜居带外缘的行星实际上可能无法保持温暖和宜居。在本文中,我使用简单的方程的气候和CO $_2$预算的行星在宜居带,可以捕捉系统的定性行为。用这些方程,我推导出一个有效的外边缘的宜居带的分析公式,包括限制所施加的CO $_2$放气率。然后,我表明,气候之间的循环雪球状态和温暖的气候是唯一可能超出这个限制,如果在雪球气候的风化率小于CO $_2$出气率(否则稳定的雪球状态的结果)。我推导出一个分析解决方案的气候周期,包括一个公式,他们在这个限制期间。这项工作使我们能够探索定性的影响风化过程的有效外缘的宜居带,这是很重要的,因为风化参数化是不确定的。

英文摘要:

The habitable zone concept is important because it focuses the scientific search for extraterrestrial life and aids the planning of future telescopes. Recent work has shown that planets near the outer edge of the habitable zone might not actually be able to stay warm and habitable if CO$_2$ outgassing rates are not large enough to maintain high CO$_2$ partial pressures against removal by silicate weathering. In this paper I use simple equations for the climate and CO$_2$ budget of a planet in the habitable zone that can capture the qualitative behavior of the system. With these equations I derive an analytical formula for an effective outer edge of the habitable zone, including limitations imposed by the CO$_2$ outgassing rate. I then show that climate cycles between a Snowball state and a warm climate are only possible beyond this limit if the weathering rate in the Snowball climate is smaller than the CO$_2$ outgassing rate (otherwise stable Snowball states result). I derive an analytical solution for the climate cycles including a formula for their period in this limit. This work allows us to explore the qualitative effects of weathering processes on the effective outer edge of the habitable zone, which is important because weathering parameterizations are uncertain.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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