TOI-2109: An Ultrahot Gas Giant on a 16 hr Orbit

Wong, Ian and Shporer, Avi and Zhou, George ORCID: https://orcid.org/0000-0002-4891-3517 and Kitzmann, Daniel and Komacek, Thaddeus D. and Tan, Xianyu and Tronsgaard, Rene and Buchhave, Lars A. and Vissapragada, Shreyas and Greklek-McKeon, Michael and Rodriguez, Joseph E. and Ahlers, John P. and Quinn, Samuel N. and Furlan, Elise and Howell, Steve B. and Bieryla, Allyson and Heng, Kevin and Knutson, Heather A. and Collins, Karen A. and McLeod, Kim K. and Berlind, Perry and Brown, Peyton and Calkins, Michael L. and de Leon, Jerome P. and Esparza-Borges, Emma and Esquerdo, Gilbert A. and Fukui, Akihiko and Gan, Tianjun and Girardin, Eric and Gnilka, Crystal L. and Ikoma, Masahiro and Jensen, Eric L. N. and Kielkopf, John and Kodama, Takanori and Kurita, Seiya and Lester, Kathryn V. and Lewin, Pablo and Marino, Giuseppe and Murgas, Felipe and Narita, Norio and Palle, Enric and Schwarz, Richard P. and Stassun, Keivan G. and Tamura, Motohide and Watanabe, Noriharu and Benneke, Bjorn and Ricker, George R. and Latham, David W. and Vanderspek, Roland and Seager, Sara and Winn, Joshua N. and Jenkins, Jon M. and Caldwell, Douglas A. and Fong, William and Huang, Chelsea X. ORCID: https://orcid.org/0000-0003-0918-7484 and Mireles, Ismael and Schlieder, Joshua E. and Shiao, Bernie and Villasenor, Jesus Noel (2021) TOI-2109: An Ultrahot Gas Giant on a 16 hr Orbit. The Astronomical Journal, 162 (6):256. pp. 1-28. ISSN 0004-6256


Abstract

We report the discovery of an ultrahot Jupiter with an extremely short orbital period of 0.67247414 0.00000028 days (∼16 hr). The 1.347 0.047 R Jup planet, initially identified by the Transiting Exoplanet Survey Satellite (TESS) mission, orbits TOI-2109 (TIC 392476080) - a T eff ∼ 6500 K F-type star with a mass of 1.447 0.077 M , a radius of 1.698 0.060 R , and a rotational velocity of v sin i ∗ }=81.9\pm 1.7 km s-1. The planetary nature of TOI-2109b was confirmed through radial-velocity measurements, which yielded a planet mass of 5.02 0.75 M Jup. Analysis of the Doppler shadow in spectroscopic transit observations indicates a well-aligned system, with a sky-projected obliquity of λ = 1. 7 1. 7. From the TESS full-orbit light curve, we measured a secondary eclipse depth of 731 46 ppm, as well as phase-curve variations from the planet's longitudinal brightness modulation and ellipsoidal distortion of the host star. Combining the TESS-band occultation measurement with a K s -band secondary eclipse depth (2012 80 ppm) derived from ground-based observations, we find that the dayside emission of TOI-2109b is consistent with a brightness temperature of 3631 69 K, making it the second hottest exoplanet hitherto discovered. By virtue of its extreme irradiation and strong planet-star gravitational interaction, TOI-2109b is an exceptionally promising target for intensive follow-up studies using current and near-future telescope facilities to probe for orbital decay, detect tidally driven atmospheric escape, and assess the impacts of H2 dissociation and recombination on the global heat transport.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Astrophysics (1 Aug 2018 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Astrophysics (1 Aug 2018 -)
Date Deposited: 02 Mar 2022 00:23
Last Modified: 02 Mar 2022 00:23
Uncontrolled Keywords: Exoplanet astronomy (486); Hot Jupiters (753); Exoplanet detection methods (489); Transit photometry (1709); Radial velocity (1332)
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
Identification Number or DOI: https://doi.org/10.3847/1538-3881/ac26bd
URI: http://eprints.usq.edu.au/id/eprint/47221

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