JWST Reveals CH$_4$, CO$_2$, and H$_2$O in a Metal-rich Miscible Atmosphere on a Two-Earth-Radius Exoplanet
Björn Benneke, Pierre-Alexis Roy, Louis-Philippe Coulombe, Michael Radica, Caroline Piaulet, Eva-Maria Ahrer, Raymond Pierrehumbert, Joshua Krissansen-Totton, H… 展开作者
Björn Benneke, Pierre-Alexis Roy, Louis-Philippe Coulombe, Michael Radica, Caroline Piaulet, Eva-Maria Ahrer, Raymond Pierrehumbert, Joshua Krissansen-Totton, Hilke E. Schlichting, Renyu Hu, Jeehyun Yang, Duncan Christie, Daniel Thorngren, Edward D. Young, Stefan Pelletier, Heather A. Knutson, Yamila Miguel, Thomas M. Evans-Soma, Caroline Dorn, Anna Gagnebin, Jonathan J. Fortney, Thaddeus Komacek, Ryan MacDonald, Eshan Raul, Ryan Cloutier, Lorena Acuna, David Lafrenière, Charles Cadieux, René Doyon, Luis Welbanks, Romain Allart
Even though sub-Neptunes likely represent the most common outcome of planet formation, their natures remain poorly understood. In particular, planets near 1.5-2.5$\,R_\oplus$ often have bulk densities that can be explained equally well with widely different compositions and interior structures, resulting in grossly divergent implications for their formation. Here, we present the full 0.6-5.2$\,μ\mathrm{m}$ JWST NIRISS/SOSS+NIRSpec/G395H transmission spectrum of the 2.2$\,R_\oplus$ TOI-270d ($4.78\,M_\oplus$, $T_\mathrm{eq}$=350-380 K), delivering unprecedented sensitivity for atmospheric characterization in the sub-Neptune regime. We detect five vibrational bands of CH$_4$ at 1.15, 1.4, 1.7, 2.3, and 3.3$\,μ$m (9.4$σ$), the signature of CO$_2$ at 4.3$\,μ$m (4.8$σ$), water vapor (2.5$σ$), and potential signatures of SO$_2$ at 4.0$\,μ\mathrm{m}$ and CS$_2$ at 4.6$\,μ\mathrm{m}$. Intriguingly, we find an overall highly metal-rich atmosphere, with a mean molecular weight of $5.47_{-1.14}^{+1.25}$. We infer an atmospheric metal mass fraction of $58_{-12}^{+8}\%$ and a C/O of $0.47_{-0.19}^{+0.16}$, indicating that approximately half the mass of the outer envelope is in high-molecular-weight volatiles (H$_2$O, CH$_4$, CO, CO$_2$) rather than H$_2$/He. We introduce a sub-Neptune classification scheme and identify TOI-270d as a "miscible-envelope sub-Neptune" in which H$_2$/He is well-mixed with the high-molecular-weight volatiles in a miscible supercritical metal-rich envelope. For a fully miscible envelope, we conclude that TOI-270d's interior is $90_{-4}^{+3}\,$wt$\,\%$ rock/iron, indicating that it formed as a rocky planet that accreted a few wt % of H$_2$/He, with the overall envelope metal content explained by magma-ocean/envelope reactions without the need for significant ice accretion. TOI-270d may well be an archetype of the overall population of sub-Neptunes.
Piercing through the Haze: Characterizing Titan-like terrestrial exoplanets with JWST
Johns Hopkins Applied Physics Laboratory（约翰斯·霍普金斯大学应用物理实验室）；University of Wyoming, School of Computing（怀俄明大学计算机学院）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；NASA Ames Research Center（美国宇航局艾姆斯研究中心）；Bay Area Environmental Research Institute（湾区环境研究所）
ExoEcho: Exoplanet Ephemerides Change Observations. III. A JWST Survey for Transit Timing Variations of 37 Exoplanets
School of Physics and Astronomy, Sun Yat-sen University（中山大学物理学院）；CSST Science Center for the Guangdong-Hong Kong-Macau Great Bay Area, Sun Yat-sen University（中山大学粤港澳大湾区空间望远镜科学中心）
Information content of JWST transmission spectroscopy of the exoplanet HAT-P-12b from the optical to the mid-infrared
KU Leuven（荷语鲁汶大学）；University of Edinburgh（爱丁堡大学）；SRON Space Research Organisation Netherlands（荷兰空间研究所）；Max-Planck-Institut für Astronomie (MPIA)（马克斯·普朗克天文学研究所）；Leiden University（莱顿大学）；University of Groningen（格罗宁根大学）；Radboud University（拉德堡德大学）；Université Paris-Saclay（巴黎萨克雷大学）；Université Paris Cité（巴黎西岱大学）
The dark and featureless surface of rocky exoplanet LHS 3844 b from JWST mid-infrared spectroscopy
Center for Astrophysics, Harvard & Smithsonian（哈佛-史密松天体物理中心）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；University of Chicago（芝加哥大学）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；California Institute of Technology（加州理工学院）；Peking University（北京大学）；The Pennsylvania State University（宾夕法尼亚州立大学）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）
How Does Thermal Scattering Shape the Infrared Spectra of Cloudy Exoplanets? A Theoretical Framework and Consequences for Atmospheric Retrievals in the JWST era
A second visit to Eps Ind Ab with JWST: new photometry confirms ammonia and suggests thick clouds in the exoplanet atmosphere of the closest super-Jupiter
Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；University of Texas at Austin（德克萨斯大学奥斯汀分校）；Space Telescope Science Institute（太空望远镜科学研究所）；Heidelberg University（海德堡大学）；Leiden University（莱顿大学）
The Unrealised Interdisciplinary Advantage of Observing High Mass Transiting Exoplanets and Brown Dwarfs -- Strategic Exoplanet Initiatives with HST and JWST White Paper
Observations of Transiting Exoplanets with the James Webb Space Telescope (JWST), Publications of the Astronomical Society of the Pacific (PASP), December 2014
On the synergetic use of Ariel and JWST for exoplanet atmospheric science
Kapteyn Institute University of Groningen（格罗宁根大学卡普坦研究所）；Université Paris-Saclay Université Paris Cité CEA CNRS AIM（巴黎萨克雷大学 巴黎西岱大学 CEA CNRS AIM）；King’s College London（伦敦国王学院）；LIRA Observatoire de Paris Université PSL CNRS Sorbonne Université Univ. Paris Cité Sorbonne Paris Cité（巴黎天文台 PSL大学 CNRS 索邦大学 巴黎西岱大学）；Department of Physics McGill University（麦吉尔大学物理系）；Department of Earth & Planetary Sciences McGill University（麦吉尔大学地球与行星科学系）；University of Valencia（瓦伦西亚大学）；INAF Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切特里天文台）；Space Telescope Science Institute（太空望远镜科学研究所）；SRON Space Research Organisation Netherlands（荷兰空间研究组织）；Astrobiology Center（天体生物学中心）；National Astronomical Observatory of Japan（日本国立天文台）
Quantifying the differences in transmission and emission spectra for hot irradiated gaseous exoplanet atmospheres: A comparison of 1D and 3D modeling using JWST
A Homogeneous Survey of JWST MIRI Transmission Spectra of 10 Exoplanets
Institute of Astronomy, University of Cambridge（剑桥大学天文学研究所）；Space Telescope Science Institute（太空望远镜科学研究所）；School of Physics and Astronomy, Cardiff University（卡迪夫大学物理与天文学院）
Molecular mapping of an exoplanet with JWST: NH3 detection in the temperate super-Jupiter Epsilon Indi Ab
Institut de Recherche en Astrophysique et Planétologie（天体物理学与行星学研究所在）；École polytechnique, Institut Polytechnique de Paris（巴黎综合理工学院，巴黎理工学院）；Observatoire de Paris（巴黎天文台）
利用JWST红外光谱和交叉相关技术，对直接成像的温带超级木星Epsilon Indi Ab进行分子测绘，可靠探测到NH3、H2O、CH4，并边缘性探测到CO2，验证了该方法在强恒星污染下的有效性。
The MUSCLES Extension for Atmospheric Transmission Spectroscopy: Spectral energy distributions for 20 exoplanet host stars that JWST observed in Cycle 1
University of Colorado（科罗拉多大学）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；Vanderbilt University（范德堡大学）；Hamburger Sternwarte（汉堡天文台）；University of Texas, Austin（德克萨斯大学奥斯汀分校）；Southwest Research Institute（西南研究院）
Prioritizing High-Precision Photometric Monitoring of Exoplanet and Brown Dwarf Companions with JWST -- Strategic Exoplanet Initiatives with HST and JWST White Paper
Investing in the Unrivaled Potential of Wide-Separation Sub-Jupiter Exoplanet Detection and Characterisation with JWST -- Strategic Exoplanet Initiatives with HST and JWST White Paper
