THE NATURE OF THE ATMOSPHERE OF THE TRANSITING SUPER-EARTH GJ 1214b
THE NATURE OF THE ATMOSPHERE OF THE TRANSITING SUPER-EARTH GJ 1214b
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凌日超级地球 GJ 1214b 大气层的性质
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
J. Fortney
中科院分区：
文献类型：
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作者：
E. Miller;J. Fortney
新发现的行星GJ 1214 b是第一颗已知的凌日超级地球，需要大量大气来解释其观测到的质量和半径。这颗行星的结构模型预测，它可能拥有至少0.05%的行星总质量的H-He包层。然而，没有显著的H-He大气的模型并没有完全被现有的数据排除。在这里，我们探索了一系列可能的行星大气，从太阳组成的气体，到纯二氧化碳或水（蒸汽）。我们目前的传输和发射光谱，这些情况下。我们发现，如果GJ 1214 b拥有一个富氢的大气层的预期，那么这样的大气层的主要过境深度将在一个高达0.3%的水平上变化的波长的函数，相对于它的M-矮星主机星星的背景光。利用目前的天基仪器有可能获得这一精度水平的观测。因此，成功探测到这颗行星在0.1%水平上的传输信号将证实行星大气层中富含氢的性质。因此，在这种精度水平上的透射光谱学可以提供第一次一瞥来回答超级地球质量体系（1-10 M）的行星是否更接近大型类地行星或小型气体巨行星的问题。
The newly discovered planet GJ 1214b is the first known transiting super-Earth requiring a significant atmosphere to explain its observed mass and radius. Models for the structure of this planet predict that it likely possesses an H–He envelope of at least 0.05% of the total mass of the planet. However, models without a significant H–He atmosphere are not entirely ruled out by the available data. Here, we explore a range of possible atmospheres for the planet, ranging from solar composition gas, to pure CO2 or water (steam). We present transmission and emission spectra for each of these cases. We find that, if GJ 1214b possesses a hydrogen-rich atmosphere as expected, then the primary transit depth for such an atmosphere would vary at a level of up to 0.3% as a function of wavelength, relative to the background light of its M-dwarf host star. Observations at this level of precision are potentially obtainable with current space-based instrumentation. Successful detection of the transmission signature of this planet at the ∼0.1% level would therefore provide confirmation of the hydrogen-rich nature of the planetary atmosphere. It follows that transmission spectroscopy at this level of precision could provide a first glimpse into answering the question of whether planets in the super-Earth mass regime (1–10 M⊕) more closely resemble large terrestrial planets or small gas giant planets.