Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs II: Properties of 11 T-dwarfs
Michael R. Line, Mark S. Marley, Michael C. Liu, Ben Burningham, Caroline V. Morley, Natalie R. Hinkel, Johanna Teske, Jonathan J. Fortney, Roxana Lupu, Richard Freedman
备注：
Accepted ApJ. Supplemental material including full posteriors will be included through the link in the published ApJ article
Brown dwarf spectra are rich in information revealing of the chemical and physical processes operating in their atmospheres. We apply a recently developed atmospheric retrieval tool to an ensemble of late T-dwarf (600-800K) near infrared spectra. With these spectra we are able to place direct constraints the molecular abundances of H$_2$O, CH$_4$, CO, CO$_2$, NH$_3$, H$_2$S, and Na+K, gravity, thermal structure (and effective temperature), photometric radius, and cloud optical depths. We find that ammonia, water, methane, and the alkali metals are present and well constrained in all 11 objects. From the abundance constraints we find no significant trend in the water, methane, or ammonia abundances with temperature, but find a very strong ($>$25$σ$) increasing trend in the alkali metal abundances with effective temperature, indicative of alkali rainout. We also find little evidence for optically thick clouds. With the methane and water abundances, we derive the intrinsic atmospheric metallicity and carbon-to-oxygen ratios. We find in our sample, that metallicities are typically sub solar and carbon-to-oxygen ratios are somewhat super solar, different than expectations from the local stellar population. We also find that the retrieved vertical thermal profiles are consistent with radiative equilibrium over the photospheric regions. Finally, we find that our retrieved effective temperatures are lower than previous inferences for some objects and that our radii are larger than expectations from evolutionary models, possibly indicative of un-resolved binaries. This investigation and methodology represents a paradigm in linking spectra to the determination of the fundamental chemical and physical processes governing cool brown dwarf atmospheres.
SPHEREx Ultracool Dwarf spectrophotometric Atlas (SUDA): Atmospheric and Fundamental Parameters of Ultracool Dwarfs
CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台光学天文重点实验室）；School of Astronomy and Space Sciences, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学天文与前沿科学研究中心）
Ultraviolet-Driven Atmospheric Degeneracies Challenge Conventional Biosignature Frameworks for Terrestrial Planets with Ultracool M Dwarf Hosts: An Archean-Analog TRAPPIST-1 e Case Study
University of California, Riverside（加州大学河滨分校）；Blue Marble Space Institute of Science（蓝大理石太空科学研究所）；University of Maryland, Baltimore County（马里兰大学巴尔的摩县分校）；NASA Goddard Space Flight Center（NASA戈达德太空飞行中心）；SETI Institute（搜寻地外文明研究所）；NASA Ames Research Center（NASA艾姆斯研究中心）
Uniform Forward-Modeling Analysis of Ultracool Dwarfs. IV. Benchmarking the Sonora Diamondback and Saumon & Marley (2008) Atmospheric Models Across Late-M, L, and T types with Low-Resolution 0.8-2.5 $μ$m Spectroscopy
University of California, Santa Cruz（加州大学圣克鲁兹分校）；University of California, Berkeley（加州大学伯克利分校）；University of Rochester（罗切斯特大学）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；University of Arizona（亚利桑那大学）；University of California, Santa Barbara（加州大学圣塔芭芭拉分校）
The Hawaii Infrared Parallax Program. VI. The Fundamental Properties of 1000+ Ultracool Dwarfs and Planetary-mass Objects Using Optical to Mid-IR SEDs and Comparison to BT-Settl and ATMO 2020 Model Atmospheres
A SPHEREx Pipeline and Spectral Library for Ultracool Dwarfs
Planétarium de Montréal, Espace pour la Vie（蒙特利尔天文馆，生命空间）；Trottier Institute for Research on Exoplanets, Université de Montréal, Département de Physique（特罗蒂埃系外行星研究所，蒙特利尔大学）；Department of Astrophysics, American Museum of Natural History（美国自然历史博物馆天体物理学部）；School of Physical Sciences, The Open University（开放大学物理科学学院）；United States Naval Observatory, Flagstaff Station（美国海军天文台弗拉格斯塔夫站）
JWST/NIRSpec Spectra for Three Ultracool Brown Dwarfs Detected in Extragalactic Surveys: Further Evidence for Phosphine Absorption
Steward Observatory, University of Arizona（亚利桑那大学斯图尔德天文台）；School of Physics, Trinity College Dublin, University of Dublin（都柏林大学三一学院物理系）；Department of Astronomy and Astrophysics, University of California, San Diego（加州大学圣地亚哥分校天体物理学与天文学系）；Monta Vista High School（蒙塔维塔高中）；The Department of Astronomy & Astrophysics, The Pennsylvania State University（宾夕法尼亚州立大学天体物理学与天文学系）；Department of Planetary Sciences, Lunar & Planetary Laboratory, University of Arizona（亚利桑那大学月球与行星实验室行星科学系）；School of Earth and Space Exploration, Arizona State University（亚利桑那州立大学地球与空间探索学院）；Department of Physics and Astronomy, University of Manitoba（曼尼托巴大学物理与天文学系）
Clouds and Chemistry Across the Brown Dwarf T-Y Sequence: Insights from JWST Atmospheric Retrievals
Ludwig Maximilian University（路德维希-马克西米利安大学）；University of Bern（伯尔尼大学）；ARTORG Center for Biomedical Engineering Research, University of Bern（伯尔尼大学ARTORG生物医学工程研究中心）；University College London（伦敦大学学院）；University of Warwick（华威大学）
Discovering and Characterising Exoplanets and Ultracool Dwarfs with the Square Kilometre Array
University of Amsterdam（阿姆斯特丹大学）；ASTRON, The Netherlands Institute for Radio Astronomy（荷兰射电天文研究所）；Observatoire de Paris（巴黎天文台）；National Astronomical Observatory of Japan（日本国立天文台）；University of Tokyo（东京大学）；California Institute of Technology（加州理工学院）；University of Colorado Boulder（科罗拉多大学博尔德分校）；University of Groningen（格罗宁根大学）
A Comprehensive Atmospheric Retrieval Analysis of 22 James Webb Space Telescope Spectral Energy Distributions of Cool Brown Dwarfs
University of Toledo（托莱多大学）；Dordt University（道特大学）；University of Arizona（亚利桑那大学）；University of Hertfordshire（赫特福德大学）；United States Naval Observatory（美国海军天文台）；Caltech（加州理工学院）
Tempawral: A Time-Resolved Retrieval Framework for Variable Brown Dwarfs and Exoplanets
University of Hertfordshire（赫特福德大学）；University of Sheffield（谢菲尔德大学）；Université de Montréal（蒙特利尔大学）；National Astronomical Observatory of Japan（日本国立天文台）；SOKENDAI（综合研究大学院大学）；American Museum of Natural History（美国自然历史博物馆）；The Graduate Center City University of New York（纽约市立大学研究生中心）；Trinity College Dublin, The University of Dublin（都柏林三一学院，都柏林大学）
