Optical phase curve of the ultra-hot Jupiter WASP-121b

V. Bourrier; D. Kitzmann; T. Kuntzer; V. Nascimbeni; M. Lendl; B. Lavie; H. J. Hoeijmakers; L. Pino; D. Ehrenreich; K. Heng; R. Allart; H. M Cegla; X. Dumusque; C. Melo; N. Astudillo-Defru; D. A. Caldwell; M. Cretignier; H. Giles; C. E. Henze; J. Jenkins; C. Lovis; F. Murgas; F. Pepe; G. R. Ricker; M. E. Rose; S. Seager; D. Segransan; A. Suarez-Mascareno; S. Udry; R. Vanderspek; A. Wyttenbach

doi:10.1051/0004-6361/201936647

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arXiv · 1909.03010

Optical phase curve of the ultra-hot Jupiter WASP-121b

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Abstract

We present the analysis of TESS optical photometry of WASP-121b, which reveal the phase curve of this transiting ultra-hot Jupiter. Its hotspot is located at the substellar point, showing inefficient heat transport from the dayside (2870 K) to the nightside ($<$ 2200 K) at the altitudes probed by TESS. The TESS eclipse depth, measured at the shortest wavelength to date for WASP-121b, confirms the strong deviation from blackbody planetary emission. Our atmospheric retrieval on the complete emission spectrum supports the presence of a temperature inversion, which can be explained by the presence of VO and possibly TiO and FeH. The strong planetary emission at short wavelengths could arise from an H$^{-}$ continuum.

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V. Bourrier, D. Kitzmann, T. Kuntzer, V. Nascimbeni, M. Lendl, B. Lavie, H. J. Hoeijmakers, L. Pino, D. Ehrenreich, K. Heng, R. Allart, H. M Cegla, X. Dumusque, C. Melo, N. Astudillo-Defru, D. A. Caldwell, M. Cretignier, H. Giles, C. E. Henze, J. Jenkins, C. Lovis, F. Murgas, F. Pepe, G. R. Ricker, M. E. Rose, S. Seager, D. Segransan, A. Suarez-Mascareno, S. Udry, R. Vanderspek, A. Wyttenbach. 2019-09-06. Optical phase curve of the ultra-hot Jupiter WASP-121b. https://doi.org/10.1051/0004-6361/201936647

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