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arXiv 1607.08147astro-ph.EP
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恒星耀斑对系外行星化学成分和光谱的影响

Influence of Stellar Flares on the Chemical Composition of Exoplanets and Spectra

Olivia Venot, Marco Rocchetto, Shaun Carl, Aysha Hashim, Leen Decin

摘要:

到目前为止,已经发现了3000多颗系外行星,并且越来越多的系外行星光谱观测正在进行。人们热切期待着未来的仪器,因为它们将能够提供比目前更精确和灵敏的光谱数据。需要考虑的一个重要方面是恒星大气的时间扰动,它会影响行星的组成,从而影响光谱,并可能导致对行星稳态大气组成的错误假设。我们专注于扰动,来自主恒星的耀斑事件,显着增加光子通量撞击系外行星大气的形式。在某些情况下,特别是对于M星,这种突然的增加可能会持续几个小时。我们的目标是回答这个问题,在多大程度上恒星耀斑是能够修改的化学成分的行星大气,从而影响所产生的光谱。我们使用一个一维热光化学模型来研究位于恒星AD狮子座周围的两个假设的行星的中性大气成分。这颗活跃的恒星已经在耀斑期间被观测到。我们使用光谱数据从这个耀斑事件来模拟两个假设的行星的大气的化学成分的演变。我们计算合成光谱,以评估观测的影响。入射光子通量的增加会影响一些重要物种的化学丰度,这些物种的高度与1巴的大气压力有关,如果在过境期间进行,可能导致行星光谱的变化。

英文摘要:

More than 3000 exoplanets have been detected so far, and more and more spectroscopic observations of exoplanets are performed. Future instruments are eagerly awaited as they will be able to provide spectroscopic data with a greater accuracy and sensitivity than what is currently available. An important aspect to consider is temporal stellar atmospheric disturbances that can influence the planetary composition, and hence spectra, and potentially can lead to incorrect assumptions about the steady-state atmospheric composition of the planet. We focus on perturbations that come from the host star in the form of flare events that significantly increase the photon flux impingement on the exoplanet atmosphere. In some cases, and particularly for M stars, this sudden increase may last for several hours. We aim at answering the question to what extent a stellar flare is able to modify the chemical composition of the planetary atmosphere and, therefore influence the resulting spectra. We use a 1D thermo-photochemical model to study the neutral atmospheric composition of two hypothetic planets located around the star AD Leo. This active star has already been observed during a flare. We use the spectroscopic data from this flare event to simulate the evolution of the chemical composition of the atmospheres of the two hypothetic planets. We compute synthetic spectra to evaluate the implications for observations. The increase of the incoming photon flux affects the chemical abundances of some important species down to altitudes associated with an atmospheric pressure of 1 bar, that can lead to variations in planetary spectra if performed during transit.

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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