TOI-1431b/MASCARA-5b: A Highly Irradiated Ultra-Hot Jupiter Orbiting One of the Hottest & Brightest Known Exoplanet Host Stars [EPA]

http://arxiv.org/abs/2104.12078


We present the discovery of a highly irradiated and moderately inflated ultra-hot Jupiter, TOI-1431b/MASCARA-5b (HD 201033b), first detected by NASA’s Transiting Exoplanet Survey Satellite mission (TESS) and the Multi-site 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 $K=294.1\pm1.1$ m s$^{-1}$. A joint analysis of TESS, MuSCAT2, and LCOGT photometry, radial velocity measurements, and the spectral energy distribution of the host star reveals that TOI-1431b has a mass of $M_{p}=3.14_{-0.18}^{+0.19}$ $\rm{M_J}$ ($1000\pm60$ M${\oplus}$), an inflated radius of $R{p}=1.51\pm0.06$ $\rm{R_J}$ ($16.9_{-0.6}^{+0.7}$ R${\oplus}$), and an orbital period of $P=2.65022\pm0.00001$ d. The planet orbits a bright ($\mathrm{V}=8.049$ mag) and young ($0.29^{+0.32}{-0.19}$ Gyr) Am type star with $T_{\rm eff}=7690^{+400}{-250}$ $\rm{K}$, resulting in a highly irradiated planet with an incident flux of $\langle F \rangle=7.24^{+0.68}{-0.64}\times$10$^9$ erg s$^{-1}$ cm$^{-2}$ ($5300^{+500}{-470}\mathrm{S{\oplus}}$) and an equilibrium temperature of $T_{eq}=2370\pm100$ K. TESS photometry also reveals a secondary eclipse with a depth of $124\pm5$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 $T_\mathrm{day}=2983^{+63}{-68}$ K and $T\mathrm{night}=2556^{+62}_{-65}$ K, the second hottest measured nightside temperature. The planet’s low day/night temperature contrast ($\sim$400 K) suggests very efficient heat transport between the dayside and nightside hemispheres.

Read this paper on arXiv…

B. Addison, E. Knudstrup, I. Wong, et. al.
Tue, 27 Apr 21
81/85

Comments: Submitted for publication in the Astronomical Journal. 38 pages, 22 figures, and 5 tables