UV SURFACE ENVIRONMENT OF EARTH-LIKE PLANETS ORBITING FGKM STARS THROUGH GEOLOGICAL EVOLUTION
UV SURFACE ENVIRONMENT OF EARTH-LIKE PLANETS ORBITING FGKM STARS THROUGH GEOLOGICAL EVOLUTION
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DOI：
10.1088/0004-637x/806/1/137
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发表时间：
2015-06-10
影响因子：
4.9
通讯作者：
Sasselov, D.
中科院分区：
文献类型：
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作者：
Rugheimer, S.;Segura, A.;Sasselov, D.
主星星的紫外线环境影响大气中的光化学，最终影响类地行星表面的紫外线环境，从而影响生命起源和进化的条件。我们通过其地质演化，模拟了环绕FGKM星的地球大小的行星的表面紫外辐射环境。我们探索了四种不同类型的大气层，对应于3.9 Gyr前的早期地球大气层，以及三种大气层，覆盖了2.0 Gyr前，0.8 Gyr前和现代地球的氧气上升到今天的水平。除了计算地球表面的紫外线通量外，我们还使用DNA损伤作为生物损伤的代理，对生物有效辐照度进行建模。我们发现，一个前生物地球（3.9 Gyr前）围绕F0 V星星运行，接收到的生物有效辐射是早期太阳周围的6倍，是现代地球-太阳水平的3520倍。一个围绕GJ 581（M3.5 V）运行的前生物地球接收到的生物有效辐射要少300倍，大约是现代地球-太阳水平的2倍。这里计算的紫外线通量提供了一个网格的模型紫外线环境的演变过程中的类地行星绕恒星的范围。这些模型可用于光生物学实验和生命前化学和早期生命进化实验的输入。
The UV environment of a host star affects the photochemistry in the atmosphere, and ultimately the surface UV environment for terrestrial planets and therefore the conditions for the origin and evolution of life. We model the surface UV radiation environment for Earth-sized planets orbiting FGKM stars in the circumstellar Habitable Zone for Earth through its geological evolution. We explore four different types of atmospheres corresponding to an early-Earth atmosphere at 3.9 Gyr ago and three atmospheres covering the rise of oxygen to present-day levels at 2.0 Gyr ago, 0.8 Gyr ago, and modern Earth. In addition to calculating the UV flux on the surface of the planet, we model the biologically effective irradiance, using DNA damage as a proxy for biological damage. We find that a pre-biotic Earth (3.9 Gyr ago) orbiting an F0V star receives 6 times the biologically effective radiation as around the early Sun and 3520 times the modern Earth-Sun levels. A pre-biotic Earth orbiting GJ 581 (M3.5 V) receives 300 times less biologically effective radiation, about 2 times modern Earth-Sun levels. The UV fluxes calculated here provide a grid of model UV environments during the evolution of an Earth-like planet orbiting a range of stars. These models can be used as inputs into photo-biological experiments and for pre-biotic chemistry and early life evolution experiments.