http://arxiv.org/abs/2004.10767
We present the detection and characterization of the full-orbit phase curve and secondary eclipse of the ultra-hot Jupiter WASP-33b at optical wavelengths, along with the pulsation spectrum of the host star. We analyzed data collected by the Transiting Exoplanet Survey Satellite (TESS) during Sector 18. WASP-33b belongs to a very short list of highly irradiated exoplanets that were discovered from the ground and were afterwards visited by TESS. WASP-33b’s host star, of delta Scuti type, shows non-radial pulsations in the milli-magnitude regime, with periods comparable to that of the primary transit. Carrying out a detailed determination of the pulsation spectrum of the host star, we find 29 pulsation frequencies with a signal-to-noise ratio higher than 4. After cleaning the light curve for the stellar pulsations we confidently report a secondary eclipse depth of 305.8 +/- 35.5 parts-per-million (ppm), along with an amplitude of the phase curve of 100.4 +/- 13.1 ppm and a corresponding westward offset between the region of maximum brightness and the substellar point of 28.7 +/- 7.1 degrees, making WASP-33b one of the few planets with such an offset found so far. Our derived Bond albedo, A_B = 0.369 +/- 0.050, and heat recirculation efficiency, epsilon = 0.189 +/- 0.014, reconfirm WASP-33b to be similar in behaviour to other hot Jupiters, despite the high irradiation received from its host star. Connecting the amplitude of the phase curve to the primary transit and secondary eclipse depths, we determine the day and night side brightness temperatures of WASP-33b to be 3014 +/- 60 K and 1605 +/- 45 K, respectively. From the detection of photometric variations due to gravitational interactions, we estimated a planet mass of M_P = 2.81 +/- 0.53 M_Jup. Analyzing the stellar pulsations in the frame of the planetary orbit, we find no signals of star-planet interactions.
C. Essen, M. Mallonn, C. Borre, et. al.
Fri, 24 Apr 20
46/63
Comments: 19 pages, 15 figures
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