TESS Observations of the WASP-121 b Phase Curve
Name
Daylan_2021_AJ_161_131.pdf
Description
Published version
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6.72 MB
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Author(s)
Daylan, Tansu
Günther, Maximilian N
Mikal-Evans, Thomas
Sing, David K
Wong, Ian
Shporer, Avi
Niraula, Prajwal
Wit, Julien de
Koll, Daniel DB
Parmentier, Vivien
Date Issued
February 2021
Journal
Astronomical Journal
Publisher
American Astronomical Society
Version
Final published version
Abstract
© 2021. The American Astronomical Society. All rights reserved. We study the red-optical photometry of the ultrahot Jupiter WASP-121 b as observed by the Transiting Exoplanet Survey Satellite (TESS) and model its atmosphere through a radiative transfer simulation. Given its short orbital period of ∼1.275 days, inflated state, and bright host star, WASP-121 b is exceptionally favorable for detailed atmospheric characterization. Toward this purpose, we use allesfitter to characterize its full red-optical phase curve, including the planetary phase modulation and secondary eclipse. We measure the day- and nightside brightness temperatures in the TESS passband as 3012-+4240 and 2022-+602254 K, respectively, and do not find a statistically significant phase shift between the brightest and substellar points. This is consistent with inefficient heat recirculation on the planet. We then perform an atmospheric retrieval analysis to infer the dayside atmospheric properties of WASP-121 b, such as its bulk composition, albedo, and heat recirculation. We confirm the temperature inversion in the atmosphere and suggest H-, TiO, and VO as potential causes of the inversion, absorbing heat at optical wavelengths at low pressures. Future Hubble Space Telescope and James Webb Space Telescope observations of WASP-121 b will benefit from its first full phase curve measured by TESS.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
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DOI of Published Version
https://doi.org/10.3847/1538-3881/ABD8D2
