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arXiv 2104.06216astro-ph.EP
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雪球事件发生在宜居带内边缘附近的可能性有多大?

How likely are Snowball episodes near the inner edge of the habitable zone?

R. Wordsworth

摘要:

了解全球冰川何时发生在类地行星上是气候演化研究的一个重大挑战。大多数关于温室气体(如CO2)在类地行星上如何随时间演变的模型都是确定性的,但地球气候历史的复杂性和非线性性质激发了对非确定性气候模型的研究。在这里,一个最简单的随机模型的CO2演化和气候的类地行星与不完美的CO2恒温器进行了研究。结果表明,在这个模型中,随着恒星光度的增加,平均大气CO浓度的降低使气候变得越来越不稳定,一旦接收到的恒星通量接近当今地球,就会出现低温状态的漂移。除非气候反馈总是迫使CO2浓度的变化随着接收到的恒星通量迅速下降,否则这意味着靠近宜居带内边缘的类地行星可能会相当频繁地进入雪球状态。对类地系外行星的日冕和颜色变化的观测应该可以让这一预测在未来得到直接检验。

英文摘要:

Understanding when global glaciations occur on Earth-like planets is a major challenge in climate evolution research. Most models of how greenhouse gases like CO2 evolve with time on terrestrial planets are deterministic, but the complex, nonlinear nature of Earth's climate history motivates study of non-deterministic climate models. Here a maximally simple stochastic model of CO2 evolution and climate on an Earth-like planet with an imperfect CO2 thermostat is investigated. It is shown that as stellar luminosity is increased in this model, the decrease in the average atmospheric CO concentration renders the climate increasingly unstable, with excursions to a low-temperature state common once the received stellar flux approaches that of present-day Earth. Unless climate feedbacks always force the variance in CO2 concentration to decline rapidly with received stellar flux, this means that terrestrial planets near the inner edge of the habitable zone may enter Snowball states quite frequently. Observations of the albedos and color variation of terrestrial-type exoplanets should allow this prediction to be tested directly in the future.

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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