发表机构
SRON, Netherlands Institute for Space Research; Institute of Astronomy and Astrophysics, Academia Sinica; Leiden Observatory, Leiden University（荷兰空间研究所; 中央研究院天文及天文物理研究所; 莱顿大学莱顿天文台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究模拟M矮星反复耀斑对富金属气态巨行星大气的长期影响，发现耀斑导致CH4、CO2、SO2等物种丰度持久改变及光谱特征变化，表明需考虑恒星活动并采用概率反演方法。
AI 中文摘要
在这项工作中，我们模拟了反复发生的恒星耀斑对富含金属的气态系外行星大气的长期影响。利用来自基准耀斑模型的合成耀斑光谱，并结合光化学动力学代码，我们追踪了大气成分随时间的变化。我们进一步通过在不同时间步将这些丰度剖面输入辐射传输代码来分析光谱变异性。我们的模拟显示，与静止状态相比，关键大气物种（如CH4、CO2和SO2）出现了变异性和持续性变化。极端耀斑事件导致高层大气中分子迅速消耗，光谱特征暂时消失，尤其是7-8微米处的SO2特征，其偏移约75 ppm。许多物种在耀斑后并未完全恢复到静止状态，导致丰度发生持久变化，尤其是SO2和CO2，这些是推断大气金属丰度时的关键物种。我们还探讨了反复耀斑的累积效应，表明H2O和CH4等物种呈现递减的丰度趋势，半衰期约为28至31年。这些结果表明，耀斑活动在塑造绕M矮星运行的巨型气态系外大气的短期和长期成分及光谱特征方面起着重要作用，强调在表征此类大气时需要考虑恒星活动。我们的发现还强调，所模拟行星的大气并非静态，表明对大气丰度采用概率方法可能比静态反演更合适，特别是对于绕活跃恒星运行的气态行星。
英文摘要
In this work, we model the long-term impact of recurrent stellar flares on the atmospheres of metal-rich gaseous exoplanets. Using synthetic flare spectra from a fiducial flare model integrated with a photochemical kinetics code, we track the changes in atmospheric composition with time. We further analyze the spectral variability by feeding these abundance profiles into a radiative transfer code at various time steps. Our simulations showed variability and persistent changes in key atmospheric species, such as CH4, CO2, and SO2, when compared to their quiescent state. Extreme flare events cause rapid depletion of molecules in the upper atmosphere and a temporary disappearance of spectral features, especially the SO2 feature at 7-8 microns, which shifted by about 75 ppm. Many species did not fully return to their quiescent state after flares, resulting in lasting changes in abundance, especially for SO2 and CO2, key species when inferring the atmospheric metallicty. We also explored the cumulative effects of recurrent flares, showing that species like H2O and CH4 followed a decreasing abundance trend, with half-lives of around 28 to 31 years. These results indicate that flare activity plays a significant role in shaping both the short- and long-term atmospheric composition and spectral features of giant gaseous exoplanets orbiting M-dwarf stars, underscoring the need to account for stellar activity when characterising such atmospheres. Our findings also highlight that the atmosphere of the modelled planet is not static, suggesting that a probabilistic approach to atmospheric abundances may be more appropriate than static retrievals, particularly for gaseous planets orbiting active stars.
CommentsAccepted for publication in MNRAS
