The phase curve of the ultra-hot Jupiter WASP-167b as seen by TESS

Abstract

Context. Ultra-hot Jupiters (UHJs) orbiting pulsating A/F stars represent an important subset of the exoplanetary demographic. They are excellent candidates for the study of exoplanetary atmospheres, and are astrophysical laboratories for the investigation of planet-to- star interactions. Aims. We analysed the TESS light curve of the WASP-167 system, consisting of an F1V star and a substellar companion on a ~2.02 day orbit. Methods. We modelled the combination of the ellipsoidal variability and the Doppler beaming to measure the mass of WASP-167b, and the reflection effect to obtain constraints on the geometric albedo, while placing a special emphasis on noise separation. We implemented a basic model to determine the dayside (TDay), nightside (TNight), and intrinsic (TInternal) temperatures of WASP-167b, and put a constraint on its Bond albedo. Results. We confirm the transit parameters of the planet seen in the literature. We find that a resonant ~2P−1 stellar signal (which may originate from planet-to-star interactions) interferes with the phase curve analysis. After careful and thought-out treatment of this signal, we find Mp = 0.34 ± 0.22 MJ. We measure a dayside temperature of 2790 ± 100 K, classifying WASP-167b as an UHJ. We find a 2σ upper limit of 0.51 on its Bond albedo, and determine the geometric albedo at 0.34 ± 0.11 (1σ uncertainty). Conclusions. With an occultation depth of 106.8 ± 27.3 ppm in the TESS passband, the UHJ WASP-167b is an excellent target for atmospheric studies, especially those at thermal wavelength ranges, where the stellar pulsations are expected to be less influential.