We calculate the mass loss driven by MHD waves from hot Jupiters by using MHD simulations in one-dimensional flux tubes. If a gaseous planet has magnetic field, MHD waves are excited by turbulence at the surface, dissipate at the upper atmosphere, and drive gas outflows. Our calculation shows that mass loss rates are comparable to the observed mass loss rates of hot Jupiters, therefore it is suggested that gas flow driven by MHD waves can plays an important role in the mass loss from gaseous planets. The mass loss rate varies dramatically with radius and mass of a planet: a gaseous planet with a small mass but with inflated radius produces very large mass loss rate. We also derive an analytical expression for the dependence of mass loss rate on planet radius and mass that is in good agreement with the numerical calculation. The mass loss rate also depends on the amplitude of velocity dispersion at the surface of a planet. Thus we expect to infer the condition of the surface and the internal structure of a gaseous planet from future observations of mass loss rate from various exoplanets.
Planetary atmospheric escape and disk formation around WDJ0914+1914
Instituto de Astronomía Teórica y Experimental (CONICET-UNC)（理论与实验天体物理研究所）；Instituto de Astrofísica de La Plata, CCT La Plata-CONICET-UNLP（拉普拉塔天体物理研究所）；Departamento de Física, Universidad Técnica Federico Santa María（圣马利亚技术大学物理系）；Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México（墨西哥国立自治大学核科学研究所）；Department of Physics, University of Warwick（华威大学物理系）
Hydrogen airglow from an escaping ultrahot Jupiter atmosphere
California Institute of Technology（加州理工学院）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；Massachusetts Institute of Technology（麻省理工学院）；Imperial College London（伦敦帝国学院）；University of Hawaii at Mānoa（夏威夷大学马诺阿分校）；University of California Berkeley（加州大学伯克利分校）
The Colorado Ultraviolet Transit Experiment (CUTE) Mission Overview
大气逃逸是影响许多行星结构、组成和演化的基本过程。逃逸的信号在靠近的气态系外行星上是可以探测到的，这些行星围绕明亮的恒星运行，这是由于它们的母恒星发出了高水平的极紫外线辐射。科罗拉多紫外线凌日实验（CUTE）是一个立方体卫星飞行任务，旨在利用近紫外线恒星亮度分布对附近近距离行星的扩展大气层进行调查。CUTE的有效载荷是一个放大NUV（2479~--~3306 Ang）摄谱仪，由一个矩形卡塞格伦望远镜（206 mm x 84 mm）馈电;光谱图记录在一个背照式紫外增强CCD上。科学有效载荷集成到6 U Blue Canyon Technology XB 1总线中。CUTE于2021年9月27日发射到极地低地球轨道，并在在轨调试期后一直在进行这项凌日光谱调查。本文介绍了任务的动机，发展道路，并展示了小卫星进行这类科学的潜力，提出初步的在轨科学观测。主要的科学任务将于2022~--~2023年进行，公开的数据档案将于2023年上线。
The GAPS programme at TNG LXXI. A sub-Neptune suitable for atmospheric characterization in a multiplanet and mutually inclined system orbiting the bright K dwarf TOI-5789 (HIP 99452)
INAF - Osservatorio Astrofisico di Torino（意大利国家天体物理研究所都灵天文台）；INAF - Osservatorio Astronomico di Palermo（意大利国家天体物理研究所巴勒莫天文台）；Instituto de Astrofísica de Canarias (IAC)（加那利天体物理学研究所）；Departamento de Astrofísica, Universidad de La Laguna (ULL)（拉帕马大学天体物理学系）；INAF-Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Space Research Institute, Austrian Academy of Sciences（奥地利科学院空间研究所）
