论文标题
恒星耀斑对绕气体系外行星的化学成分和透射光谱的影响
Impact of stellar flares on the chemical composition and transmission spectra of gaseous exoplanets orbiting M dwarfs
论文作者
论文摘要
活性M矮人的恒星耀斑会影响近距离气体巨头的大气组成，并可能导致时间依赖时间的传输光谱。我们旨在检查各种耀斑的影响，各种能量，持续时间和发生频率不同，对近距离逆转占主导地位的气候的封闭，潮汐气态行星的组成和光谱的影响。我们使用了一系列的伪2D光学动力学模型，这些模型通过赤道喷射流进行了对流，以模拟气态行星（有效温度800 K）的中性分子组成，从而绕着燃烧的M矮人绕。然后，我们计算了晚上和早晨肢体的传输光谱。我们发现，在CH4和NH3中，白天和傍晚的肢体的上部区域大量耗尽，直到几天后，散发性能为$ 2 \ times 10^{33} $ ERG。 C2H2和HCN的摩尔级分在夜间和早晨的肢体上提高了三个因子，在光解散物种的日复一日对流。 CH4的耗竭可在傍晚的肢体上将过境深度减少100-300份（PPM），而C2H2的产量将14微米的特征提高到早晨的肢体最高350 ppm。我们发现，重复的耀斑将大气驱动到与其前剥离分布不同的组成，这转化为透射光谱的永久修改。我们表明，直到火炬事件发生后的几天，单个高能耀斑可能会影响近距离气体巨头的大气，在此期间，它们的传输光谱被数百ppm改变了。重复的耀斑对活跃星周围的系外行星的未来检索分析具有重要意义，因为大气组成和所得的光谱特征与不包括燃烧的模型有很大不同。
Stellar flares of active M dwarfs can affect the atmospheric composition of close-orbiting gas giants, and can result in time-dependent transmission spectra. We aim to examine the impact of a variety of flares, differing in energy, duration, and occurrence frequency, on the composition and spectra of close-orbiting, tidally locked gaseous planets with climates dominated by equatorial superrotation. We used a series of pseudo-2D photo- and thermochemical kinetics models, which take advection by the equatorial jet stream into account, to simulate the neutral molecular composition of a gaseous planet (effective temperature 800 K) that orbits a flaring M dwarf. We then computed transmission spectra for the evening and morning limb. We find that the upper regions of the dayside and evening limb are heavily depleted in CH4 and NH3 up to several days after a flare with a total radiative energy of $ 2 \times 10^{33} $ erg. Molar fractions of C2H2 and HCN are enhanced up to a factor three on the nightside and morning limb after day-to-nightside advection of photodissociated species. CH4 depletion reduces transit depths by 100-300 parts per million (ppm) on the evening limb and C2H2 production increases the 14 micron feature up to 350 ppm on the morning limb. We find that repeated flaring drives the atmosphere to a composition that differs from its pre-flare distribution and that this translates to a permanent modification of the transmission spectrum. We show that single high-energy flares can affect the atmospheres of close-orbiting gas giants up to several days after the flare event, during which their transmission spectra are altered by several hundred ppm. Repeated flaring has important implications for future retrieval analyses of exoplanets around active stars, as the atmospheric composition and resulting spectral signatures substantially differ from models that do not include flaring.
