Dr. Rabus, Markus

2021, Dr. Rabus, Markus, Addison, Brett, Knudstrup, Emil, Wong, Ian, Hébrard, Guillaume, Dorval, Patrick, Snellen, Ignas, Albrecht, Simon, Bello-Arufe, Aaron, Almenara, Jose-Manuel, Boisse, Isabelle, Bonfils, Xavier, Dalal, Shweta, Demangeon, Olivier, Hoyer, Sergio, Kiefer, Flavien, Santos, N. C., Nowak, Grzegorz, Luque, Rafael, Stangret, Monika, Palle, Enric, Tronsgaard, René, Antoci, Victoria, Buchhave, Lars A., Günther, Maximilian N., Daylan, Tansu, Murgas, Felipe, Parviainen, Hannu, Esparza-Borges, Emma, Crouzet, Nicolas, Narita, Norio, Fukui, Akihiko, Kawauchi, Kiyoe, Watanabe, Noriharu, Johnson, Marshall, Otten, Gilles, Jan-Talens, Geert, Cabot, Samuel, Fischer, Debra, Grundahl, Frank, Fredslun-Andersen, Mads, Jessen-Hansen, Jens, Pallé, Pere, Shporer, Avi, Ciardi, David, Clark, Jake, Wittenmyer, Robert, Wright, Duncan, Horner, Jonathan, Collins, Karen, Jensen, Eric, Kielkopf, John, Schwarz, Richard, Srdoc, Gregor, Yilmaz, Mesut, Senavci, Hakan, Diamond, Brendan, Harbeck, Daniel, Komacek, Thaddeus, Smith, Jeffrey, Wang, Songhu, Eastman, Jason, Stassun, Keivan, Latham, David, Vanderspek, Roland, Seager, Sara, Winn, Joshua, Jenkins, Jon, Louie, Dana, Bouma, Luke, Twicken, Joseph, Levine, Alan, McLean, Brian

We present the discovery of a highly irradiated and moderately inflated ultrahot Jupiter, TOI-1431b/MASCARA5 b (HD 201033b), first detected by NASA’s Transiting Exoplanet Survey Satellite mission (TESS) and the Multisite All-Sky Camera (MASCARA). The signal was established to be of planetary origin through radial velocity measurements obtained using SONG, SOPHIE, FIES, NRES, and EXPRES, which show a reflex motion of K = 294.1 ± 1.1 m s−1. A joint analysis of the TESS and ground-based photometry and radial velocity measurements reveals that TOI-1431b has a mass of Mp = 3.12 ± 0.18 MJ (990 ± 60 M⊕), an inflated radius of Rp = 1.49 ± 0.05 RJ (16.7 ± 0.6 R⊕), and an orbital period of P = 2.650237 ± 0.000003 days. Analysis of the spectral energy distribution of the host star reveals that the planet orbits a bright (V = 8.049 mag) and young ( -+ 0.29 0.19 0.32 Gyr) Am type star with = -+ Teff 7690 250 400 K, resulting in a highly irradiated planet with an incident flux of á ñ= ´ - + F 7.24 0.64 0.68 109 erg s−1 cm−2 ( - + 5300 470 SÅ 500 ) and an equilibrium temperature of Teq = 2370 ± 70 K. TESS photometry also reveals a secondary eclipse with a depth of - + 127 5 4 ppm as well as the full phase curve of the planet’s thermal emission in the red-optical. This has allowed us to measure the dayside and nightside temperature of its atmosphere as Tday = 3004 ± 64 K and Tnight = 2583 ± 63 K, the second hottest measured nightside temperature. The planet’s low day/night temperature contrast (∼420 K) suggests very efficient heat transport between the dayside and nightside hemispheres. Given the host star brightness and estimated secondary eclipse depth of ∼1000 ppm in the K band, the secondary eclipse is potentially detectable at near-IR wavelengths with ground-based facilities, and the planet is ideal for intensive atmospheric characterization through transmission and emission spectroscopy from space missions such as the James Webb Space Telescope and the Atmospheric Remote-sensing Infrared Exoplanet Large-survey.