论文标题
恒星耀斑与亮度：XUV引起的大气逃逸和行星宜居性
Stellar Flares versus Luminosity: XUV-induced Atmospheric Escape and Planetary Habitability
论文作者
论文摘要
太空天气在行星气氛的发展中起着重要作用。观察结果表明，恒星耀斑在宽的能量范围内发射能量（10^30-10^38 ERG），其中一部分在X射线和极端紫外线（XUV）中。这些耀斑在行星的上层大气中加热，导致逃逸率提高，并在一段时间内导致大气侵蚀。观察结果还表明，原始的陆地行星可以增大巨大的H/HE信封。恒星辐射会随着时间的流逝侵蚀这些protoatmospheres，并且这种侵蚀的程度对行星的宜居性具有影响。我们使用能量限制的方程来计算这些protoatmosphers的流体动力逃逸速率，这些量大球受到XUV恒星耀斑和光度的照射。我们使用与苔丝观察到的492 fgm恒星的耀斑频率分布来估计可居住区行星的大气损失。我们发现，对于大多数恒星，亮度引起的逃生是主要的损失机制，耀斑的贡献很小。但是，耀斑主导着$ \ sim $ 20 \％M4-M10星的损失机制。 M0-M4恒星最有可能完全侵蚀其原始气氛和次要气氛，而M4-M10最不可能侵蚀次要大气。我们讨论了这些结果对行星宜居性的含义。
Space weather plays an important role in the evolution of planetary atmospheres. Observations have shown that stellar flares emit energy in a wide energy range (10^30-10^38 ergs), a fraction of which lies in X-rays and extreme ultraviolet (XUV). These flares heat the upper atmosphere of a planet, leading to increased escape rates, and can result in atmospheric erosion over a period of time. Observations also suggest that primordial terrestrial planets can accrete voluminous H/He envelopes. Stellar radiation can erode these protoatmospheres over time, and the extent of this erosion has implications for the planet's habitability. We use the energy-limited equation to calculate hydrodynamic escape rates from these protoatmospheres irradiated by XUV stellar flares and luminosity. We use the Flare-Frequency Distribution of 492 FGKM stars observed with TESS to estimate atmospheric loss in Habitable Zone planets. We find that for most stars, luminosity-induced escape is the main loss mechanism, with a minor contribution from flares. However, flares dominate the loss mechanism of $\sim$20\% M4-M10 stars. M0-M4 stars are most likely to completely erode both their proto- and secondary atmospheres, and M4-M10 are least likely to erode secondary atmospheres. We discuss the implications of these results on planetary habitability.
