Some super Earths and mini Neptunes will likely have thick atmospheres that are not H2-dominated. We have developed a photochemistry-thermochemistry kinetic-transport model for exploring the compositions of thick atmospheres on super Earths and mini Neptunes, applicable for both H2-dominated atmospheres and non-H2-dominated atmospheres. Using this model to study thick atmospheres for wide ranges of temperatures and elemental abundances, we classify them into hydrogen-rich atmospheres, water-rich atmospheres, oxygen-rich atmospheres, and hydrocarbon-rich atmospheres. We find that carbon has to be in the form of CO2 rather than CH4 or CO in a H2-depleted water-dominated thick atmosphere, and that the preferred loss of light elements from an oxygen-poor carbon-rich atmosphere leads to formation of unsaturated hydrocarbons (C2H2 and C2H4). We apply our self-consistent atmosphere models to compute spectra and diagnostic features for known transiting low-mass exoplanets GJ 1214 b, HD 97658 b, and 55 Cnc e. For GJ 1214 b like planets we find that (1) C2H2 features at 1.0 and 1.5 micron in transmission and C2H2 and C2H4 features at 9-14 micron in thermal emission are diagnostic for hydrocarbon-rich atmospheres; (2) a detection of water-vapor features and a confirmation of nonexistence of methane features would provide sufficient evidence for a water-dominated atmosphere. In general, our simulations show that chemical stability has to be taken into account when interpreting the spectrum of a super Earth/mini Neptune. Water-dominated atmospheres only exist for carbon to oxygen ratios much lower than the solar ratio, suggesting that this kind of atmospheres could be rare.
Thermochemistry and vertical mixing in the tropospheres of Uranus and Neptune: How convection inhibition can affect the derivation of deep oxygen abundances
Three outstanding physical questions for K2-18 b and other temperate sub-Neptunes
Institute of Astronomy & Astrophysics, Academia Sinica（中央研究院天文及天文物理研究所）；HFML-FELIX（高频磁场设施-费利克斯实验室）；JHU Applied Physics Laboratory（约翰斯·霍普金斯大学应用物理实验室）；ETH Zurich, Institute for Particle Physics & Astrophysics（苏黎世联邦理工学院粒子物理与天体物理研究所）；Deutsches Elektronen-Synchrotron DESY（德国电子同步加速器中心）；Department of Earth and Planetary Sciences, University of California, Riverside（加州大学河滨分校地球与行星科学系）；Virtual Planetary Laboratory, University of Washington（华盛顿大学虚拟行星实验室）；Blue Marble Space Institute of Science（蓝大理石空间科学研究所）；Department of Astrophysics, IMAPP, Radboud University（拉德堡德大学IMAPP天体物理学系）；SRON Leiden（莱顿荷兰太空研究所）
Escape of Water- and Metal-enriched Atmospheres from compact Hot mini-Neptunes with CHAIN
University of Bern（伯尔尼大学）；Space Research Institute, Austrian Academy of Sciences（奥地利科学院空间研究所）；European Space Agency (ESA), European Space Research and Technology Centre (ESTEC)（欧洲空间局（ESA）欧洲空间研究与技术中心（ESTEC））；Department of Astronomy & Astrophysics, University of Chicago（芝加哥大学天文与天体物理系）
Exploring atmospheres of hot mini-Neptunes and extrasolar giant planets orbiting different stars with application to HD 97658b, WASP-12b, CoRoT-2b, XO-1b and HD 189733b
Quantified Estimation of Molecular Detections across Different Classes of Neptunian Atmospheres Using Cross-Correlation Spectroscopy: Prospects for Future Extremely Large Telescopes with High-Resolution Spectrographs
JWST-SUPER I: New insights into irradiated warm Neptunes atmospheres from MIRI observations of HD 106315 c
Space Telescope Science Institute（太空望远镜科学研究所）；Department of Astrophysics/IMAPP, Radboud University（拉德堡德大学天体物理系/IMAPP）；Radboud University（拉德堡德大学）；SRON, Space Research Organisation Netherlands（荷兰空间研究组织 SRON）；Institute of Astronomy & Astrophysics, Academia Sinica（中央研究院天文及天文物理研究所）；School of Physics & Astronomy, Space Park Leicester, University of Leicester（莱斯特大学物理与天文学学院，太空公园莱斯特）；University of Vienna, Department of Astrophysics（维也纳大学天体物理系）；ETH Zürich, Institute for Particle Physics and Astrophysics（苏黎世联邦理工学院粒子物理与天体物理研究所）；ASTRON, Netherlands Institute for Radio Astronomy（荷兰射电天文研究所 ASTRON）；Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM（巴黎萨克雷大学、巴黎西岱大学、法国原子能和替代能源委员会、法国国家科学研究中心、天体物理学与信息学实验室）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）
First Detection of Exoplanetary Cannabinoids: Evidence for THC and CBD in the Atmosphere of K2-18b
University of Chicago（芝加哥大学）；Coffeeshop Institute for Atmospheric Research (CIAR)（咖啡研究所大气研究中心）；Dutch Foundation for Elevated Sciences（荷兰提升科学基金会）；Institut de Fumée Atmosphérique（大气烟雾研究所）；Centre National de la Recherche Très Relaxante (CNRTR)（国家极度放松研究中心）；Max-Planck-Institut für Entspannungsforschung（马克斯·普朗克放松研究所）；Deutsches Zentrum für Grüne Chemie (DZGC)（德国绿色化学中心）；Royal Observatory of the Highlands（高地皇家天文台）；Scottish Institute for Hazy Atmospheres (SIHA)（苏格兰雾状大气研究所）；BC Chronic Research Institute（BC慢性病研究所）；Canadian Centre for Chill Exoplanetology (CCCE)（加拿大休闲系外行星学中心）；Instituto de Astrofísica Relajada（放松天体物理研究所）；Centro de Estudios Cannabinoides Extraterrestres (CECE)（地外大麻素研究中心）
