HIP 41378 observed by CHEOPS

Author(s): S. Sulis, L. Borsato, S. Grouffal, H. P. Osborn, A. Santerne, A. Brandeker, M. N. Günther, A. Heitzmann, M. Lendl, M. Fridlund, D. Gandolfi, Y. Alibert, R. Alonso, T. Bárczy, D. Barrado Navascues, S. C.C. Barros, W. Baumjohann, T. Beck, W. Benz, M. Bergomi, N. Billot, A. Bonfanti, C. Broeg, A. Collier Cameron, C. Corral Van Damme, A. C.M. Correia, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, L. Delrez, O. D.S. Demangeon, B. O. Demory, A. Derekas, B. Edwards, D. Ehrenreich, A. Erikson, A. Fortier, L. Fossati, K. Gazeas, M. Gillon, M. Güdel, Ch Helling, S. Hoyer, K. G. Isaak, L. L. Kiss, J. Korth, K. W.F. Lam, J. Laskar, A. Lecavelier Des Etangs, D. Magrin, P. F.L. Maxted, C. Mordasini, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, D. Piazza, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, N. C. Santos, G. Scandariato, D. Ségransan, A. E. Simon, A. M.S. Smith, S. G. Sousa, M. Stalport, M. Steinberger, Gy M. Szabó, A. Tuson, S. Udry, S. Ulmer-Moll, V. Van Grootel, J. Venturini, E. Villaver, N. A. Walton, T. G. Wilson, D. Wolter, T. Zingales
Abstract: HIP 41378 d is a long-period planet that has only been observed to transit twice, three years apart, with K2. According to stability considerations and a partial detection of the Rossiter- McLaughlin effect, P_d = 278.36 d has been determined to be the most likely orbital period. We targeted HIP 41378 d with CHEOPS at the predicted transit timing based on P_d = 278.36 d, but the observations show no transit. We find that large (> 22.4 h) transit timing variations (TTVs) could explain this non-detection during the CHEOPS observation window. We also investigated the possibility of an incorrect orbital solution, which would have major implications for our knowledge of this system. If P_d ≠ 278.36 d, the periods that minimize the eccentricity would be 101.22 d and 371.14 d. The shortest orbital period will be tested by TESS, which will observe HIP 41378 in Sector 88 starting in January 2025. Our study shows the importance of a mission like CHEOPS, which today is the only mission able to make long observations (i.e., from space) to track the ephemeris of long-period planets possibly affected by large TTVs.
Organisation(s): Department of Astrophysics
External organisation(s): Aix-Marseille Université, Osservatorio Astronomico, Universität Bern, Massachusetts Institute of Technology, Stockholm University, Science and Operations Department - Science Division (SCI-SC), Université de Genève, Leiden University, Chalmers University of Technology, University of Turin, Institute of Astrophysics of the Canary Islands, University of La Laguna, Admatis Ltd., European Space Astronomy Centre (ESA), Universidade do Porto, Österreichische Akademie der Wissenschaften (ÖAW), University of St. Andrews, Universidade de Coimbra, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), INAF-Osservatorio Astrofisico di Torino, Lund University, Université de Liège, Katholieke Universiteit Leuven, Eötvös Loránd University Budapest, SRON Netherlands Institute for Space Research , National & Kapodistrian University of Athens, Technische Universität Graz, Eötvös Loránd Research Network, Lund Observatory, Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, Keele University, INAF-Osservatorio Astrofisico di Catania, University of Padova, University of Warwick, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Freie Universität Berlin (FU), Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), HUN-REN Hungarian Research Network
Journal: Astronomy and Astrophysics
Volume: 686
No. of pages: 6
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202449689
Publication date: 06-2024
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/b6b50d02-c4b5-424e-a7b0-1a6606de537a

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