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arXiv 0906.2193astro-ph.EPastro-ph.IM
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探测系外行星上的行星地球化学循环:大气特征和SO2的情况

Detecting planetary geochemical cycles on exoplanets: Atmospheric signatures and the case of SO2

L. Kaltenegger, D. Sasselov

摘要:

我们研究了行星大气的光谱,以获得系外行星上不同全球地球化学循环的低分辨率可检测特征-以硫循环为例。作为比较行星学的第一步,我们推导出第一代空间和地面望远镜的低分辨率可探测特征。我们假设类地系外行星(类地行星和超级地球)的表面和大气层通常会受到特定地球化学循环的控制。在这里,我们集中在硫循环驱动的SO2和H2S的脱气,然后由它们的转化为其他含硫的物种,这是明显区别于由CO2脱气驱动的碳循环。由于火山活动的增加,硫循环可能是具有活动构造的干燥超级地球上占主导地位的全球地球化学循环。我们计算行星的发射,反射和透射光谱从0.4到40微米的高和低分辨率,以评估可检测的功能,使用当前和太古代地球模型与不同的SO2和H2S浓度,以探索岩石行星上的还原和氧化宜居环境。我们发现特定的光谱特征,可观察到低分辨率的行星大气与高浓度的SO2和H2S。因此,第一代空间和地面望远镜可以测试我们对岩石行星地球化学循环的理解,并可能区分由碳和硫循环主导的行星环境。

英文摘要:

We study the spectrum of a planetary atmosphere to derive detectable features in low resolution of different global geochemical cycles on exoplanets - using the sulphur cycle as our example. We derive low resolution detectable features for first generation space- and ground- based telescopes as a first step in comparative planetology. We assume that the surfaces and atmospheres of terrestrial exoplanets (Earth-like and super-Earths) will most often be dominated by a specific geochemical cycle. Here we concentrate on the sulphur cycle driven by outgassing of SO2 and H2S followed by their transformation to other sulphur-bearing species which is clearly distinguishable from the carbon cycle which is driven by outgassing of CO2. Due to increased volcanism, the sulphur cycle is potentially the dominant global geochemical cycle on dry super-Earths with active tectonics. We calculate planetary emission, reflection and transmission spectrum from 0.4 to 40 micrometer with high and low resolution to assess detectable features using current and Archean Earth models with varying SO2 and H2S concentrations to explore reducing and oxidizing habitable environments on rocky planets. We find specific spectral signatures that are observable with low resolution in a planetary atmosphere with high SO2 and H2S concentration. Therefore first generation space and ground based telescopes can test our understanding of geochemical cycles on rocky planets and potentially distinguish planetary environments dominated by the carbon and sulphur cycle.

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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