Constraining the reflective properties of WASP-178 b using CHEOPS photometry

Author(s): I. Pagano, G. Scandariato, V. Singh, M. Lendl, D. Queloz, A. E. Simon, S. G. Sousa, A. Brandeker, A. Collier Cameron, S. Sulis, V. Van Grootel, T. G. Wilson, Y. Alibert, R. Alonso, G. Anglada, T. Bárczy, D. Barrado Navascues, S. C.C. Barros, W. Baumjohann, M. Beck, T. Beck, W. Benz, N. Billot, X. Bonfils, L. Borsato, C. Broeg, G. Bruno, L. Carone, S. Charnoz, C. Corral Van Damme, Sz Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, L. Delrez, O. D.S. Demangeon, B. O. Demory, D. Ehrenreich, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Güdel, M. N. Günther, Ch Helling, S. Hoyer, K. G. Isaak, L. L. Kiss, E. Kopp, K. W.F. Lam, J. Laskar, A. Lecavelier Des Etangs, D. Magrin, P. F.L. Maxted, C. Mordasini, M. Munari, V. Nascimbeni, G. Olofsson, R. Ottensamer, E. Pallé, G. Peter, G. Piotto, D. Pollacco, R. Ragazzoni, N. Rando, H. Rauer, C. Reimers, I. Ribas, M. Rieder, N. C. Santos, D. Ségransan, A. M.S. Smith, M. Stalport, M. Steller, Gy M. Szabó, N. Thomas, S. Udry, J. Venturini, N. A. Walton
Abstract: Context. Multiwavelength photometry of the secondary eclipses of extrasolar planets is able to disentangle the reflected and thermally emitted light radiated from the planetary dayside. Based on this, we can measure the planetary geometric albedo Ag, which is an indicator of the presence of clouds in the atmosphere, and the recirculation efficiency ϵ, which quantifies the energy transport within the atmosphere. Aims. We measure Ag and ϵ for the planet WASP-178 b, a highly irradiated giant planet with an estimated equilibrium temperature of 2450 K. Methods. We analyzed archival spectra and the light curves collected by CHEOPS and TESS to characterize the host WASP-178, refine the ephemeris of the system, and measure the eclipse depth in the passbands of the two telescopes. Results. We measured a marginally significant eclipse depth of 70 ± 40 ppm in the TESS passband, and a statistically significant depth of 70 ± 20 ppm in the CHEOPS passband. Conclusions. Combining the eclipse-depth measurement in the CHEOPS (λeff = 6300 Å) and TESS (λeff = 8000 Å) passbands, we constrained the dayside brightness temperature of WASP-178 b in the 2250-2800 K interval. The geometric albedo 0.1< Ag<0.35 generally supports the picture that giant planets are poorly reflective, while the recirculation efficiency ϵ >0.7 makes WASP-178 b an interesting laboratory for testing the current heat-recirculation models.
Organisation(s): Department of Astrophysics
External organisation(s): INAF-Osservatorio Astrofisico di Catania, Université de Genève, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Universität Bern, Universidade do Porto, Stockholm University, University of St. Andrews, Aix-Marseille Université, Université de Liège, 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), Österreichische Akademie der Wissenschaften (ÖAW), University of Grenoble Alpes, Osservatorio Astronomico, Université de Paris, Science and Operations Department - Science Division (SCI-SC), Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), INAF-Osservatorio Astrofisico di Torino, Lund University, Leiden University, Chalmers University of Technology, University of Turin, Technische Universität Graz, Eötvös Loránd Research Network, Eötvös Loránd University Budapest, Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, Keele University, University of Padova, University of Warwick, Technische Universität Berlin, Freie Universität Berlin (FU)
Journal: Astronomy and Astrophysics
Volume: 682
No. of pages: 15
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202346705
Publication date: 02-2024
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/7673b227-7868-4232-ab4d-545c4e6e2b86

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