Gravity-darkening Analysis of the Misaligned Hot Jupiter MASCARA-4 b

John P. Ahlers, Ethan Kruse, Knicole D. Colón, Patrick Dorval, Geert Jan Talens, Ignas Snellen, Simon Albrecht, Gilles Otten, George Ricker, Roland Vanderspek, David Latham, Sara Seager, Joshua Winn, Jon M. Jenkins, Kari Haworth, Scott Cartwright, Robert Morris, Pam Rowden, Peter Tenenbaum, Eric B. Ting

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


MASCARA-4 b is a hot Jupiter in a highly misaligned orbit around a rapidly rotating A3V star that was observed for 54 days by the Transiting Exoplanet Survey Satellite (TESS). We perform two analyses of MASCARA-4 b using a stellar gravity-darkened model. First, we measure MASCARA-4 b's misaligned orbital configuration by modeling its TESS photometric light curve. We take advantage of the asymmetry in MASCARA-4 b's transit due to its host star's gravity-darkened surface to measure MASCARA-4 b's true spin-orbit angle to be 104°. We also detect a ∼4σ secondary eclipse at 0.491 � 0.007 orbital phase, proving that the orbit is slightly eccentric. Second, we model MASCARA-4 b's insolation including gravity darkening and find that the planet's received X-ray and ultraviolet flux varies by 4% throughout its orbit. MASCARA-4 b's short-period, polar orbit suggests that the planet likely underwent dramatic orbital evolution to end up in its present-day configuration and that it receives a varying stellar irradiance that perpetually forces the planet out of thermal equilibrium. These findings make MASCARA-4 b an excellent target for follow-up characterization to better understand the orbital evolution and present-day environment of planets around high-mass stars.

Original languageEnglish (US)
Article number63
JournalAstrophysical Journal
Issue number2
StatePublished - Jan 10 2020

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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