Exoplanet X-ray irradiation and evaporation rates with eROSITA
G. Foster, K. Poppenhaeger, N. Ilic, A. Schwope
备注：
13 pages, 11 figures. To appear on A&A, Special Issue: The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the SRG Mission. Electronic data table will be made available on VizieR
High-energy irradiation is a driver for atmospheric evaporation and mass loss in exoplanets. This work is based on data from eROSITA, the soft X-ray instrument aboard SRG (Spectrum Roentgen Gamma) mission, as well as archival data from other missions, we aim to characterise the high-energy environment of known exoplanets and estimate their mass loss rates. We use X-ray source catalogues from eROSITA, XMM-Newton, Chandra and ROSAT to derive X-ray luminosities of exoplanet host stars in the 0.2-2 keV energy band with an underlying coronal, i.e. optically thin thermal spectrum. We present a catalogue of stellar X-ray and EUV luminosities, exoplanetary X-ray and EUV irradiation fluxes and estimated mass loss rates for a total of 287 exoplanets, 96 among them being characterised for the first time from new eROSITA detections. We identify 14 first time X-ray detections of transiting exoplanets that are subject to irradiation levels known to cause observable evaporation signatures in other exoplanets, which makes them suitable targets for follow-up observations.
New constraints on the future evaporation of the young exoplanets in the V1298 Tau system
年轻时的凌日行星是提高我们对系外大气层演化的理解的关键目标。我们提出了一个新的X射线观测V1298头与XMM-牛顿的结果，旨在更准确地确定高能量的辐射的四颗行星绕这个前主序星，和可能的变化，由于磁活动的短期和长期的时间尺度。在V1298 Tau系统中的行星质量的第一次测量之后，我们修改了早期对当前从行星大气逃逸率的猜测，采用我们更新的大气蒸发模型来预测该系统的未来演变。与先前的预期相反，我们发现两颗外行星不会受到Gyr时间尺度上任何蒸发的影响，而两颗较小的内行星也会受到同样的影响，除非它们的真实质量低于$\sim 40$ M $_\oplus$。这些结果证实了相对大质量的行星可以在其演化历史的早期达到质量半径图中的最终位置。
Planetary evolution with atmospheric photoevaporation I. Analytical derivation and numerical study of the evaporation valley and transition from super-Earths to sub-Neptunes
Why M-dwarf flares have limited impact on the atmospheric evaporation of sub-Neptunes and Earth-sized planets
INAF -- Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；INFN, Sezione Milano-Bicocca（意大利国家核物理研究所米兰-比可卡分部）；University of Michigan（密歇根大学）；University of Wisconsin-Madison（威斯康星大学麦迪逊分校）；INAF – Osservatorio Astronomico di Palermo（意大利国家天体物理研究所巴勒莫天文台）
Constraints on the mass and atmospheric composition and evolution of the low-density young planet DS Tuc A b
我们在ESO-3.6m处用HARPS对4000万年前的恒星DS Tuc A进行了径向速度（RV）监测，以确定其8.14天行星的行星质量，这是TESS首次揭示的。我们还在ESO-VLT上用HARPS和ESTERO观测了两次行星凌日，以测量Rossiter-McLaughlin（RM）效应和观测行星大气。我们用XMM观测测量了宿主的高能发射，以研究大气蒸发模型。我们采用高斯过程（GP）回归来模拟高水平的恒星活动，这比预期的RV行星信号大40倍以上。我们提取的透射光谱DS Tuc A b从ESTERO数据和搜索大气元素/分子通过单线检索和执行互相关与一组理论模板。通过一组模拟，我们评估了不同的情况下，大气光蒸发的行星引起的强XUV恒星辐射。虽然恒星活动阻止了我们从RV获得行星信号的清晰检测，但我们为DS Tuc A b设定了一个稳健的质量上限14.4 M_e。我们还确认，行星系几乎（但不是完全）对齐。与文献中提出的其他研究一致，恒星活动的强烈程度阻碍了对任何大气化合物的探测。从我们的网格模型中，DS Tuc A b的预期演化表明，在光蒸发阶段之后，行星半径将落在富尔顿间隙内。已知的年轻凌日行星的可用参数与其成熟对应物的分布的比较证实，前者的特点是密度低，DS Tuc A b是密度较低的行星之一。
Hard X-ray Emission in AU Mic Flares: A Minor Contributor to Planetary Atmospheric Escape
California Institute of Technology（加州理工学院）；Imperial College London（伦敦帝国理工学院）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；University of Chinese Academy of Sciences（中国科学院大学）
