The TESS Phase Curve of KELT-1b Suggests a High Dayside Albedo
Author(s)
Beatty, Thomas G; Wong, Ian; Fetherolf, Tara; Line, Michael R; Shporer, Avi; Stassun, Keivan G; Ricker, George R; Seager, Sara; Winn, Joshua N; Jenkins, Jon M; Louie, Dana R; Schlieder, Joshua E; Sha, Lizhou; Tenenbaum, Peter; Yahalomi, Daniel A; ... Show more Show less
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© 2020. The American Astronomical Society. All rights reserved. We measured the optical phase curve of the transiting brown dwarf KELT-1b (TOI 1476) using data from the TESS spacecraft. We found that KELT-1b shows significant phase variation in the TESS bandpass, with a relatively large phase amplitude of 234-44+43 ppm and a secondary eclipse depth of 371-49+47 ppm. We also measured a marginal eastward offset in the dayside hot spot of 18.°3 ± 7.°4 relative to the substellar point. We detected a strong phase-curve signal attributed to ellipsoidal distortion of the host star with an amplitude of 399 ± 19 ppm. Our results are roughly consistent with the Spitzer phase curves of KELT-1b, but the TESS eclipse depth is deeper than expected. Our cloud-free 1D models of KELT-1b's dayside emission are unable to fit the full combined eclipse spectrum. Instead, the large TESS eclipse depth suggests that KELT-1b may have a significant dayside geometric albedo of A g ∼ 0.5 in the TESS bandpass, which would agree with the tentative trend between equilibrium temperature and geometric albedo recently suggested by Wong et al. We posit that if KELT-1b has a high dayside albedo, it is likely due to silicate clouds that form on KELT-1b's nightside and are subsequently transported onto the western side of KELT-1b's dayside hemisphere before breaking up.
Date issued
2020-10Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences; Massachusetts Institute of Technology. Department of Physics; MIT Kavli Institute for Astrophysics and Space Research; Massachusetts Institute of Technology. Department of Aeronautics and AstronauticsJournal
Astronomical Journal
Publisher
American Astronomical Society
ISSN
1538-3881