TOI-1408: Discovery and Photodynamical Modeling of a Small Inner Companion to a Hot Jupiter Revealed by Transit Timing Variations

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.

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Publication Details

Journal
The Astrophysical Journal Letters
Published
2024-08-01
DOI
https://doi.org/10.3847/2041-8213/ad65fd
Citations
18
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
5.97

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article

TOI-1408: Discovery and Photodynamical Modeling of a Small Inner Companion to a Hot Jupiter Revealed by Transit Timing Variations

Michael Greklek-McKeon, Samuel N. Quinn, J. Lillo-Box, H. J. Deeg et al.
18 citations
The Astrophysical Journal Letters
Stellar, planetary, and galactic studies
5.97
article

TOI-1408: Discovery and Photodynamical Modeling of a Small Inner Companion to a Hot Jupiter Revealed by Transit Timing Variations

Michael Greklek-McKeon, Samuel N. Quinn, J. Lillo-Box, H. J. Deeg, Simon Albrecht, G. Hébrard, N. Heidari, Noriharu Watanabe, Jon M. Jenkins, S. Mathur, Michael Endl, H. Bouy, P. Chaturvedi, Alexander J. Mustill, F. Murgas, Akihiko Fukui, Ε. Πάλλη, Isabelle Boisse, Joseph D. Twicken, David W. Latham, D. Gandolfi, J. Cabrera, M. Skarka, Heather A. Knutson, J. Šubjak, Howard M. Relles, E. W. Guenther, H. Parviainen, Karen A. Collins, J. Korth, Sara Seager, I. Carleo, P. Kábath, Seth Redfield, Richard P. Schwarz, A. P. Hatzes, Eder Martioli, C. M. Persson, John H. Livingston, J. Orell-Miquel, Vincent Van Eylen, X. Delfosse, Avi Shporer, D. Barrado, M. Morales‐Calderón, Kai Ikuta, D. Hobbs, V. Pintér, P. G. Beck, Norio Narita, M. Stangret, William D. Cochran, G. Nowak, Dinil B. Palakkatharappil, R. A. García, Luis Thomas, Phillip J. MacQueen, O. D. S. Demangeon, Giuseppe Morello, Hanna L. M. Osborne, Joshua N. Winn, Gregor Srdoč, H. Kellermann
article en
18 citations

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.

The Astrophysical Journal LettersVol. 971(2)
Wesleyan University (US), Tata Institute of Fundamental Research (IN), California Institute of Technology (US), Ames Research Center (US), Centre National de la Recherche Scientifique (FR), European Southern Observatory (DE), Université de Bordeaux (FR), Universidad de La Laguna (ES), Universidade do Porto (PT), Institut Universitaire de France (FR), Lund University (SE), The Graduate University for Advanced Studies, SOKENDAI (JP), Princeton University (US), Aarhus University (DK), Université Paris Cité (FR), Masaryk University (CZ), Aix-Marseille Université (FR), Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR), Université Paris-Saclay (FR), Czech Academy of Sciences, Astronomical Institute (CZ), Observatoire de Haute-Provence (FR), Institut d'Astrophysique de Paris (FR), Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR) (DE), Nicolaus Copernicus University (PL), Astrophysique, Instrumentation et Modélisation (FR), Institute of Astrophysics and Space Sciences (PT), Max Planck Institute for Extraterrestrial Physics (DE), Laboratoire d'Astrophysique de Bordeaux (FR), Osservatorio Astrofisico di Torino (IT), Planetary Systems (United States) (US), Astrobiology Center (JP), Center for Astrophysics Harvard & Smithsonian (US), Nordic Optical Telescope (ES), CEA Paris-Saclay (FR), Centro de Astrobiología (ES), Instituto de Astrofísica de Canarias (ES), Tokyo Metropolitan Komaba High School (JP), Thüringer Landessternwarte Tautenburg (DE), Laboratório Nacional de Astrofísica (BR), Instituto de Astrofísica de Andalucía (ES), Osservatorio Astronomico di Padova (IT), National Astronomical Observatory of Japan (JP), University College London (GB), American Institute of Aeronautics and Astronautics (US), University of Turin (IT), Massachusetts Institute of Technology (US), Chalmers University of Technology (SE), The University of Tokyo (JP), Ludwig-Maximilians-Universität München (DE), Search for Extraterrestrial Intelligence (US), Université Grenoble Alpes (FR), University of Craiova (RO)
National Aeronautics and Space Administration, California Institute of Technology, Aarhus Universitet, University of Texas at Austin, Space Telescope Science Institute, NASA Exoplanet Science Institute, Universidad de La Laguna, European Space Agency, Swedish National Space Agency, Vetenskapsrådet, Ministerio de Ciencia e Innovación, Istituto Nazionale di Astrofisica, Universitetet i Oslo, Háskóli Íslands, Turun Yliopisto, Stockholms Universitet, Junta de Andalucía, Instituto de Astrofísica de Andalucía, Ames Research Center, Science and Technology Facilities Council, Japan Society for the Promotion of Science, Consejo Superior de Investigaciones Científicas, European Regional Development Fund, Agencia Estatal de Investigación, Precursory Research for Embryonic Science and Technology
Openalex Percentile: Top 3%
Stellar, planetary, and galactic studies
5.97
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