Exoplanet Volatile Carbon Content as a Natural Pathway for Haze Formation
Exoplanet Volatile Carbon Content as a Natural Pathway for Haze Formation
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DOI：
10.3847/2041-8213/acd377
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
E. Bergin;E. Kempton;M. Hirschmann;S. Bastelberger;D. Teal;G. Blake;F. Ciesla;Jie Li
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文献类型：
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作者：
E. Bergin;E. Kempton;M. Hirschmann;S. Bastelberger;D. Teal;G. Blake;F. Ciesla;Jie Li
我们探索类地行星的形成，重点是固态有机物作为挥发性碳的主要来源。对于缺水的地球，水冰线，或冰升华前沿，在行星形成盘长期以来一直是一个关键的焦点。我们认为，烟灰线，固态有机物被不可逆转地破坏的位置，也是盘中的一个关键位置。烟灰线比水雪线更接近宿主星星，并且与大多数检测到的系外行星的位置重叠。在这项工作中，我们探讨了最终的大气组成的机构，接收其材料的主要部分之间的区域的烟灰线和水冰线。我们模拟了一个富含硅酸盐的世界，其中碳质量分数为0.1%和1%，水含量可变。我们表明，作为地球化学平衡的结果，这些行星的地幔将富含还原碳，但水（氢）含量相对较低。当暴露于高层大气中的恒星紫外光子时，脱气会自然产生产生雾霾的成分。模糊的大气薄雾出现常见的系外行星清单的基础上存在的往往是无特征的传输光谱。这种烟雾可能是由下面的硅酸盐为主的地幔的高挥发性含量。虽然这种类型的行星在太阳系中没有对应的行星，但它在银河系中应该很常见，对可居住性有潜在的影响。
We explore terrestrial planet formation with a focus on the supply of solid-state organics as the main source of volatile carbon. For the water-poor Earth, the water ice line, or ice sublimation front, within the planet-forming disk has long been a key focal point. We posit that the soot line, the location where solid-state organics are irreversibly destroyed, is also a key location within the disk. The soot line is closer to the host star than the water snow line and overlaps with the location of the majority of detected exoplanets. In this work, we explore the ultimate atmospheric composition of a body that receives a major portion of its materials from the zone between the soot line and water ice line. We model a silicate-rich world with 0.1% and 1% carbon by mass with variable water content. We show that as a result of geochemical equilibrium, the mantle of these planets would be rich in reduced carbon but have relatively low water (hydrogen) content. Outgassing would naturally yield the ingredients for haze production when exposed to stellar UV photons in the upper atmosphere. Obscuring atmospheric hazes appear common in the exoplanetary inventory based on the presence of often featureless transmission spectra. Such hazes may be powered by the high volatile content of the underlying silicate-dominated mantle. Although this type of planet has no solar system counterpart, it should be common in the galaxy with potential impact on habitability.