Reconstructing the high-energy irradiation of the evaporating hot Jupiter HD 209458b
Reconstructing the high-energy irradiation of the evaporating hot Jupiter HD 209458b
复制标题
重建蒸发热木星 HD 209458b 的高能辐射
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
K. Briggs
中科院分区：
文献类型：
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作者：
T. Louden;P. Wheatley;K. Briggs
系外行星HD 209458b的大气层正在经历持续的质量损失，据信是由其恒星发出的X射线和极端紫外线(XUV)辐射造成的。由于星际吸收，这种通量的大部分不能直接观测到，但为了正确地模拟行星的光蒸发和流出的光电离，这是必需的。我们用微分发射测量(DEM)技术恢复了HD 209458的高能谱。我们建立了10^4.1~10^8K温度范围内恒星日冕和过渡区的模型，该模型受哈勃太空望远镜(HST)上的宇宙起源光谱仪(COS)测量的紫外线强度和XMM-牛顿X射线通量测量的共同约束。总氢电离光度(λ40%。然而，我们的光度与基于HST太空望远镜成像光谱仪(STIS)的结果对HD 209458b质量损失率的早期估计是一致的。精确重建的XUV辐射是确定系外行星大气质量损失率和效率的关键输入。
The atmosphere of the exoplanet HD 209458b is undergoing sustained mass loss, believed to be caused by X-ray and extreme-ultraviolet (XUV) irradiation from its star. The majority of this flux is not directly observable due to interstellar absorption, but is required in order to correctly model the photo-evaporation of the planet and photo-ionisation of the outflow. We present a recovered high energy spectrum for HD 209458 using a Differential Emission Measure (DEM) retrieval technique. We construct a model of the stellar corona and transition region for temperatures between 10^4.1 and 10^8 K which is constrained jointly by ultraviolet line strengths measured with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) and X-ray flux measurements from XMM-Newton. The total hydrogen ionising luminosity (λ 40%. However, our luminosity is compatible with early estimates of the mass loss rate of HD 209458b based on results from the HST Space Telescope Imaging Spectrograph (STIS). Precisely reconstructed XUV irradiation is a key input to determining mass loss rates and efficiencies for exoplanet atmospheres.