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Spatially Resolved Modeling of Optical Albedos for a Sample of Six Hot Jupiters

Adams, Danica J. and Kataria, Tiffany and Batalha, Natasha E. and Gao, Peter and Knutson, Heather A. (2022) Spatially Resolved Modeling of Optical Albedos for a Sample of Six Hot Jupiters. Astrophysical Journal, 926 (2). Art. No. 157. ISSN 0004-637X. doi:10.3847/1538-4357/ac3d32.

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Optical secondary eclipse measurements made by Kepler reveal a diverse set of geometric albedos for hot Jupiters with equilibrium temperatures between 1550 and 1700 K. The presence or absence of high-altitude condensates, such as Mg₂SiO₄, Fe, Al₂O₃, and TiO₂, can significantly alter optical albedos, but these clouds are expected to be confined to localized regions in the atmospheres of these tidally locked planets. Here, we present 3D general circulation models and corresponding cloud and albedo maps for six hot Jupiters with measured optical albedos in this temperature range. We find that the observed optical albedos of K2-31b and K2-107b are best matched by either cloud-free models or models with relatively compact cloud layers, while Kepler-8b’s and Kepler-17b’s optical albedos can be matched by moderately extended (f_(sed) = 0.1) parametric cloud models. HATS-11b has a high optical albedo, corresponding to models with bright Mg₂SiO₄ clouds extending to very low pressures (f_(sed) = 0.03). We are unable to reproduce Kepler-7b’s high albedo, as our models predict that the dayside will be dominated by dark Al₂O₃ clouds at most longitudes. We compare our parametric cloud model with a microphysical cloud model. We find that even after accounting for the 3D thermal structure, no single cloud model can explain the full range of observed albedos within the sample. We conclude that a better knowledge of the vertical mixing profiles, cloud radiative feedback, cloud condensate properties, and atmospheric metallicities is needed in order to explain the unexpected diversity of albedos in this temperature range.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper ItemCode and documentation
Adams, Danica J.0000-0001-9897-9680
Kataria, Tiffany0000-0003-3759-9080
Batalha, Natasha E.0000-0003-1240-6844
Gao, Peter0000-0002-8518-9601
Knutson, Heather A.0000-0002-5375-4725
Additional Information:© 2022. The Author(s). Published by the American Astronomical Society. Received 2021 May 12; revised 2021 November 12; accepted 2021 November 23; published 2022 February 21. We thank the anonymous reviewer for an interesting report that greatly helped improve the paper. P. Gao acknowledges support from NASA through the NASA Hubble Fellowship grant No. HST-HF2-51456.001-A, awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. Software: numba (Lam et al. 2015), pandas (McKinney 2010), bokeh (Bokeh Development Team 2014), NumPy (Walt 2011), IPython (Pérez & Granger 2007), Jupyter, (Kluyver et al. 2016), Virga (Batalha 2020), PICASO (Batalha et al. 2019), SQLite (sqlite3 Development Team 2019).
Funding AgencyGrant Number
NASA Hubble FellowshipHST-HF2-51456.001-A
NASANAS 5-26555
Subject Keywords:Hot Jupiters; Atmospheric clouds; Radiative transfer; Exoplanet atmospheres; Extrasolar gaseous planets
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Hot Jupiters (753); Atmospheric clouds (2180); Radiative transfer (1335); Exoplanet atmospheres (487); Extrasolar gaseous planets (2172)
Record Number:CaltechAUTHORS:20220222-706594000
Persistent URL:
Official Citation:Danica J. Adams et al 2022 ApJ 926 157
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113527
Deposited By: George Porter
Deposited On:23 Feb 2022 02:06
Last Modified:25 Jul 2022 23:14

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