A new dynamical modeling of the WASP-47 system with CHEOPS observations

Author(s): V. Nascimbeni, L. Borsato, T. Zingales, G. Piotto, I. Pagano, M. Beck, C. Broeg, D. Ehrenreich, S. Hoyer, F. Z. Majidi, V. Granata, S. G. Sousa, T. G. Wilson, V. Van Grootel, A. Bonfanti, S. Salmon, A. J. Mustill, L. Delrez, Y. Alibert, R. Alonso, G. Anglada, T. Bárczy, D. Barrado, S. C.C. Barros, W. Baumjohann, T. Beck, W. Benz, M. Bergomi, N. Billot, X. Bonfils, A. Brandeker, J. Cabrera, S. Charnoz, A. Collier Cameron, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, O. D.S. Demangeon, B. O. Demory, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Güdel, K. G. Isaak, L. L. Kiss, J. Laskar, A. Lecavelier des Etangs, M. Lendl, C. Lovis, R. Luque, D. Magrin, P. F.L. Maxted, C. Mordasini, G. Olofsson, R. Ottensamer, E. Pallé, G. Peter, D. Piazza, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, I. Ribas, N. C. Santos, G. Scandariato, D. Ségransan, A. E. Simon, A. M.S. Smith, M. Steinberger, M. Steller, Gy M. Szabó, N. Thomas, S. Udry, J. Venturini, N. A. Walton, D. Wolter
Abstract: Among the hundreds of known hot Jupiters (HJs), only five have been found to have companions on short-period orbits. Within this rare class of multiple planetary systems, the architecture of WASP-47 is unique, hosting an HJ (planet-b) with both an inner and an outer sub-Neptunian mass companion (-e and -d, respectively) as well as an additional non-transiting, long-period giant (-c). The small period ratio between planets -b and -d boosts the transit time variation (TTV) signal, making it possible to reliably measure the masses of these planets in synergy with the radial velocity (RV) technique. In this paper, we present new space- and ground-based photometric data of WASP-47b and WASP-47-d, including 11 unpublished light curves from the ESA mission CHaracterising ExOPlanet Satellite (CHEOPS). We analyzed the light curves in a homogeneous way together with all the publicly available data to carry out a global N-body dynamical modeling of the TTV and RV signals. We retrieved, among other parameters, a mass and density for planet -d of M_d = 15.5 ± 0.8 M_⊕ and ρ_d = 1.69 ± 0.22 g cm⁻³, which is in good agreement with the literature and consistent with a Neptune-like composition. For the inner planet (-e), we found a mass and density of M_e = 9.0 ± 0.5 M_⊕ and ρ_e = 8.1 ± 0.5 g cm⁻³, suggesting an Earth-like composition close to other ultra-hot planets at similar irradiation levels. Though this result is in agreement with previous RV plus TTV studies, it is not in agreement with the most recent RV analysis (at 2.8σ), which yielded a lower density compatible with a pure silicate composition. This discrepancy highlights the still unresolved issue of suspected systematic offsets between RV and TTV measurements. In this paper, we also significantly improve the orbital ephemerides of all transiting planets, which will be crucial for any future follow-up.
Organisation(s): Department of Astrophysics
External organisation(s): Osservatorio Astronomico, University of Padova, INAF-Osservatorio Astrofisico di Catania, Université de Genève, Universität Bern, Aix-Marseille Université, Universidade do Porto, University of St. Andrews, Université de Liège, Österreichische Akademie der Wissenschaften (ÖAW), Lund University, Institute of Astrophysics of the Canary Islands, University of La Laguna, Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), Admatis Ltd., European Space Astronomy Centre (ESA), University of Grenoble Alpes, Stockholm University, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université de Paris, INAF-Osservatorio Astrofisico di Torino, Leiden University, Chalmers University of Technology, Università degli Studi di Torino, Science and Operations Department - Science Division (SCI-SC), Eötvös Loránd Research Network, Eötvös Loránd University Budapest, Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, Instituto de Astrofísica de Andalucía (CSIC), University of Chicago, Keele University, University of Warwick, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Technische Universität Berlin, Freie Universität Berlin (FU)
Journal: Astronomy and Astrophysics
Volume: 673
No. of pages: 17
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202245486
Publication date: 05-2023
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/d0b4fe6b-a900-47a5-8e1d-cb52bf4d4533

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