Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4 b, and the transit-timing variations of HD 97658 b^,

Author(s)

J. V. Harre, A. M.S. Smith, S. C.C. Barros, G. Boué, Sz Csizmadia, D. Ehrenreich, H. G. Florén, A. Fortier, P. F.L. Maxted, M. J. Hooton, B. Akinsanmi, L. M. Serrano, N. M. Rosário, B. O. Demory, K. Jones, J. Laskar, V. Adibekyan, Y. Alibert, R. Alonso, D. R. Anderson, G. Anglada, J. Asquier, T. Bárczy, D. Barrado Y Navascues, W. Baumjohann, M. Beck, T. Beck, W. Benz, N. Billot, F. Biondi, A. Bonfanti, X. Bonfils, A. Brandeker, C. Broeg, J. Cabrera, V. Cessa, S. Charnoz, A. Collier Cameron, M. B. Davies, M. Deleuil, L. Delrez, O. D.S. Demangeon, A. Erikson, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Güdel, C. Hellier, K. Heng, S. Hoyer, K. G. Isaak, L. L. Kiss, A. Lecavelier Des Etangs, M. Lendl, C. Lovis, A. Luntzer, D. Magrin, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, C. M. Persson, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, G. R. Ricker, S. Salmon, N. C. Santos, G. Scandariato, S. Seager, D. Ségransan, A. E. Simon, S. G. Sousa, M. Steller, Gy M. Szabó, N. Thomas, S. Udry, B. Ulmer, V. Van Grootel, N. A. Walton, T. G. Wilson, J. N. Winn, B. Wohler

Abstract

Context. Tidal orbital decay is suspected to occur for hot Jupiters in particular, with the only observationally confirmed case of this being WASP-12 b. By examining this effect, information on the properties of the host star can be obtained using the so-called stellar modified tidal quality factor Q^′_∗, which describes the efficiency with which the kinetic energy of the planet is dissipated within the star. This can provide information about the interior of the star. Aims. In this study, we aim to improve constraints on the tidal decay of the KELT-9, KELT-16, and WASP-4 systems in order to find evidence for or against the presence of tidal orbital decay. With this, we want to constrain the Q^′_∗ value for each star. In addition, we aim to test the existence of the transit timing variations (TTVs) in the HD 97658 system, which previously favoured a quadratic trend with increasing orbital period. Methods. Making use of newly acquired photometric observations from CHEOPS (CHaracterising ExOplanet Satellite) and TESS (Transiting Exoplanet Survey Satellite), combined with archival transit and occultation data, we use Markov chain Monte Carlo (MCMC) algorithms to fit three models to the data, namely a constant-period model, an orbital-decay model, and an apsidal-precession model. Results. We find that the KELT-9 system is best described by an apsidal-precession model for now, with an orbital decay trend at over 2 σ being a possible solution as well. A Keplerian orbit model with a constant orbital period provides the best fit to the transit timings of KELT-16 b because of the scatter and scale of their error bars. The WASP-4 system is best represented by an orbital decay model at a 5 σ significance, although apsidal precession cannot be ruled out with the present data. For HD 97658 b, using recently acquired transit observations, we find no conclusive evidence for a previously suspected strong quadratic trend in the data.

Organisation(s)

Department of Astrophysics

External organisation(s)

Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Universidade do Porto, Université de recherche Paris Sciences et Lettres, Université de Genève, Stockholm University, Universität Bern, Keele University, University of Cambridge, Università degli Studi di Torino, Institute of Astrophysics of the Canary Islands, University of La Laguna, University of Warwick, Universitat Autònoma de Barcelona , Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), Science and Operations Department - Science Division (SCI-SC), Admatis Ltd., European Space Astronomy Centre (ESA), Österreichische Akademie der Wissenschaften (ÖAW), Osservatorio Astronomico, Max-Planck-Institut für extraterrestrische Physik, University of Grenoble Alpes, Université de Paris, University of St. Andrews, Lund University, Aix-Marseille Université, Université de Liège, Leiden University, Chalmers University of Technology, Eötvös Loránd Research Network, Eötvös Loránd University Budapest, Université Paris VI - Pierre-et-Marie-Curie, INAF-Osservatorio Astrofisico di Catania, University of Padova, Eidgenössische Technische Hochschule Zürich, Technische Universität Berlin, Freie Universität Berlin (FU), Massachusetts Institute of Technology, Princeton University, SETI Institute, National Aeronautics & Space Administration (NASA)

Journal

Astronomy and Astrophysics

Volume

669

No. of pages

19

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361/202244529

Publication date

01-2023

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics, 103038 Space exploration

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/85d51a47-d747-4cc7-844c-dfcc3e146b9e