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Published December 2021 | Accepted Version + Published
Journal Article Open

TOI-1431b/MASCARA-5b: A Highly Irradiated Ultrahot Jupiter Orbiting One of the Hottest and Brightest Known Exoplanet Host Stars

Abstract

We present the discovery of a highly irradiated and moderately inflated ultrahot Jupiter, TOI-1431b/MASCARA-5 b (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 ± 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 M_p = 3.12 ± 0.18 M_J (990 ± 60 M_⊕), an inflated radius of R_p = 1.49 ± 0.05 R_J (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 T_(eff) = 7690_(-250)^(+400) K, resulting in a highly irradiated planet with an incident flux of 〈F〉= 7.24_(-0.64)^(+0.68) x 10⁹ erg s⁻¹ cm⁻² (5300_(-470)^(+500) S_⊕) and an equilibrium temperature of T_(eq) = 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 T_(day) = 3004 ± 64 K and T_(night) = 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.

Additional Information

© 2021. The American Astronomical Society. Received 2021 April 11; revised 2021 August 11; accepted 2021 August 26; published 2021 December 6. Based on observations made with the Hertzsprung SONG telescope operated on the Spanish Observatorio del Teide on the island of Tenerife by the Aarhus and Copenhagen Universities and by the Instituto de Astrofísica de Canarias. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (grant agreement no.: DNRF106). Based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias under programs 59-210, 59-503, and 61-804. Based on observations collected with the SOPHIE spectrograph on the 1.93 m telescope at the Observatoire de Haute-Provence (CNRS), France. This article is based on observations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos Sánchez operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This work makes use of observations from the LCOGT network. LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF. B.A. is supported by Australian Research Council Discovery Grant DP180100972. The SONG telescope network is partially supported by the Australian Research Council Linkage, Infrastructure, Equipment and Facilities grant LE190100036. V.A. was supported by a research grant (00028173) from VILLUM FONDEN. I.W. is supported by a Heising–Simons 51 Pegasi b postdoctoral fellowship. Funding for the TESS mission is provided by NASA's Science Mission directorate. We acknowledge the use of public TESS Alert data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). T.D. acknowledges support from MIT's Kavli Institute as a Kavli postdoctoral fellow. M.Y. and H.V.S. acknowledge the support by the research fund of Ankara University (BAP) through the project 18A0759001. This work was supported by Fundação para a Ciência e a Tecnologia (FCT) and Fundo Europeu de Desenvolvimento Regional (FEDER) via COMPETE2020 through the research grants UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 and POCI-01-0145-FEDER-032113, PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953. O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by FCT. This work was supported by FCT—Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020—Programa Operacional Competitividade e Internacionalização by these grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020; PTDC/FIS-AST/32113/2017 and POCI-01-0145-FEDER-032113; PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953; PTDC/FIS-AST/28987/2017 and POCI-01-0145-FEDER-028987. S.H. acknowledges CNES funding through the grant 837319. G.H. and I.B. received funding from the French Programme National de Planétologie (PNP) of CNRS (INSU). This work is partly supported by JSPS KAKENHI Grant Nos. JP18H01265 and JP18H05439, and JST PRESTO grant No. JPMJPR1775, and a University Research Support Grant from the National Astronomical Observatory of Japan (NAOJ). M.N.G. acknowledges support from MIT's Kavli Institute as a Juan Carlos Torres Fellow. T.D.K. acknowledges support from the 51 Pegasi b Fellowship in Planetary Astronomy sponsored by the Heising–Simons Foundation. D.R.L. is supported by an appointment to the NASA Postdoctoral Program at NASA Goddard Space Flight Center, administered by Universities Space Research Association under contract with NASA. Facilities: TESS - , SONG - , SOPHIE - , NRES ELP - , NRES TLV - , FIES - , EXPRES - , LCOGT - , MuSCAT2 - , MASCARA - . Software: AstroImageJ (Collins et al. 2017), TAPIR (Jensen 2013), Allesfitter (Günther & Daylan 2019, 2021), EXOFASTv2 (Eastman et al. 2013, 2019; Eastman 2017), Astropy (Astropy Collaboration et al. 2018), Matplotlib (Hunter 2007), Wotan (Hippke et al. 2019).

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Accepted Version - 2104.12078.pdf

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Additional details

Created:
August 22, 2023
Modified:
October 23, 2023