TOI-1408: Discovery and Photodynamical Modeling of a Small Inner Companion to a Hot Jupiter Revealed by Transit Timing Variations
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Published:2024-08-01
Issue:2
Volume:971
Page:L28
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ISSN:2041-8205
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Container-title:The Astrophysical Journal Letters
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language:
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Short-container-title:ApJL
Author:
Korth JudithORCID, Chaturvedi PriyankaORCID, Parviainen HannuORCID, Carleo IlariaORCID, Endl MichaelORCID, Guenther Eike W.ORCID, Nowak GrzegorzORCID, Persson Carina M.ORCID, MacQueen Phillip J., Mustill Alexander J.ORCID, Cabrera JuanORCID, Cochran William D.ORCID, Lillo-Box JorgeORCID, Hobbs DavidORCID, Murgas FelipeORCID, Greklek-McKeon MichaelORCID, Kellermann HannaORCID, Hébrard Guillaume, Fukui AkihikoORCID, Pallé EnricORCID, Jenkins Jon M.ORCID, Twicken Joseph D.ORCID, Collins Karen A.ORCID, Quinn Samuel N.ORCID, Šubjak JánORCID, Beck Paul G.ORCID, Gandolfi DavideORCID, Mathur SavitaORCID, Deeg Hans J.ORCID, Latham David W.ORCID, Albrecht SimonORCID, Barrado DavidORCID, Boisse Isabelle, Bouy HervéORCID, Delfosse Xavier, Demangeon Olivier, García Rafael A.ORCID, Hatzes Artie P.ORCID, Heidari Neda, Ikuta KaiORCID, Kabáth PetrORCID, Knutson Heather A.ORCID, Livingston JohnORCID, Martioli EderORCID, Morales-Calderón MaríaORCID, Morello GiuseppeORCID, Narita NorioORCID, Orell-Miquel JaumeORCID, Osborne Hanna L. M., Palakkatharappil Dinil B.ORCID, Pinter Viktoria, Redfield SethORCID, Relles Howard M.ORCID, Schwarz Richard P.ORCID, Seager SaraORCID, Shporer AviORCID, Skarka MarekORCID, Srdoc Gregor, Stangret MonikaORCID, Thomas LuisORCID, Van Eylen VincentORCID, Watanabe NoriharuORCID, Winn Joshua N.ORCID
Abstract
Abstract
We report the discovery and characterization of a small planet, TOI-1408 c, on a 2.2 day orbit located interior to a previously known hot Jupiter, TOI-1408 b (P = 4.42 days, M = 1.86 ± 0.02 M
Jup, R = 2.4 ± 0.5 R
Jup) that exhibits grazing transits. The two planets are near 2:1 period commensurability, resulting in significant transit timing variations (TTVs) for both planets and transit duration variations for the inner planet. The TTV amplitude for TOI-1408 c is 15% of the planet’s orbital period, marking the largest TTV amplitude relative to the orbital period measured to date. Photodynamical modeling of ground-based radial velocity (RV) observations and transit light curves obtained with the Transiting Exoplanet Survey Satellite and ground-based facilities leads to an inner planet radius of 2.22 ± 0.06 R
⊕ and mass of 7.6 ± 0.2 M
⊕ that locates the planet into the sub-Neptune regime. The proximity to the 2:1 period commensurability leads to the libration of the resonant argument of the inner planet. The RV measurements support the existence of a third body with an orbital period of several thousand days. This discovery places the system among the rare systems featuring a hot Jupiter accompanied by an inner low-mass planet.
Funder
Swedish National Space Agency
Publisher
American Astronomical Society
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