The Influence of Coronal Mass Ejections on the Mass-loss Rates of Hot-Jupiters
The Influence of Coronal Mass Ejections on the Mass-loss Rates of Hot-Jupiters
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DOI：
10.3847/1538-4357/aa82b2
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发表时间：
2017-08
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影响因子：
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通讯作者：
A. Cherenkov;D. Bisikalo;L. Fossati;C. Möstl
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文献类型：
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作者：
A. Cherenkov;D. Bisikalo;L. Fossati;C. Möstl
热木星受到来自其宿主恒星的极端辐射和等离子体流的影响。在流体力学模型的支持下，过去的紫外线哈勃太空望远镜观测证实，这些因素导致了一个扩展包络的形成，其中一部分位于罗氏叶之外。我们利用气体动力学模拟研究了恒星风参数，即日冕物质抛射参数的时间变化对典型热木星HD 209458b包层的影响。我们考虑了三个以不同速度和密度为特征的日冕物质抛射，它们的参数来自为太阳观测到的典型日冕物质抛射。在每一次日冕物质抛射过程中，恒星风的冲压扰动撕裂了位于罗氏叶外的大部分包层。这导致了在与CME相互作用过程中质量损失率的大幅增加。我们发现，无论是否考虑日冕物质抛射，行星在穿越日冕物质抛物的整个过程中损失的质量为≈1015g。我们还发现，在1Gyr的过程中，CME碰撞造成的行星损失的质量与高能恒星辐射造成的损失相当。
Hot-Jupiters are subject to extreme radiation and plasma flows coming from their host stars. Past ultraviolet Hubble Space Telescope observations, supported by hydrodynamic models, confirmed that these factors lead to the formation of an extended envelope, part of which lies beyond the Roche lobe. We use gas-dynamic simulations to study the impact of time variations in the parameters of the stellar wind, namely that of coronal mass ejections (CMEs), on the envelope of the typical hot-Jupiter HD 209458b. We consider three CMEs characterized by different velocities and densities, taking their parameters from typical CMEs observed for the Sun. The perturbations in the ram-pressure of the stellar wind during the passage of each CME tear off most of the envelope that is located beyond the Roche lobe. This leads to a substantial increase of the mass-loss rates during the interaction with the CME. We find that the mass lost by the planet during the whole crossing of a CME is of ≈1015 g, regardless of the CME taken into consideration. We also find that over the course of 1 Gyr, the mass lost by the planet because of CME impacts is comparable to that lost because of high-energy stellar irradiation.