CHEOPS finds KELT-1b darker than expected in visible light
- Author(s)
- H. Parviainen, T. G. Wilson, M. Lendl, D. Kitzmann, E. Pallé, L. M. Serrano, E. Meier Valdes, W. Benz, A. Deline, D. Ehrenreich, P. Guterman, K. Heng, O. D.S. Demangeon, A. Bonfanti, S. Salmon, V. Singh, N. C. Santos, S. G. Sousa, Y. Alibert, R. Alonso, G. Anglada, T. Bárczy, D. Barrado Y Navascues, S. C.C. Barros, W. Baumjohann, M. Beck, T. Beck, N. Billot, X. Bonfils, A. Brandeker, C. Broeg, J. Cabrera, S. Charnoz, A. Collier Cameron, C. Corral Van Damme, Sz Csizmadia, M. B. Davies, M. Deleuil, L. Delrez, B. O. Demory, A. Erikson, J. Farinato, A. Fortier, L. Fossati, M. Fridlund, D. Gandolfi, M. Gillon, M. Güdel, S. Hoyer, K. G. Isaak, L. L. Kiss, E. Kopp, J. Laskar, A. Lecavelier Des Etangs, C. Lovis, D. Magrin, P. F.L. Maxted, M. Mecina, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, G. Peter, D. Piazza, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, G. Scandariato, D. Ségransan, A. E. Simon, A. M.S. Smith, M. Steller, Gy M. Szabó, N. Thomas, S. Udry, V. Van Grootel, N. A. Walton
- Abstract
Recent studies based on photometry from the Transiting Exoplanet Survey Satellite (TESS) have suggested that the dayside of KELT-1b, a strongly irradiated brown dwarf, is significantly brighter in visible light than what would be expected based on Spitzer observations in the infrared. We observed eight eclipses of KELT-1b with CHaracterising ExOPlanet Satellite (CHEOPS) to measure its dayside brightness temperature in the bluest passband observed so far, and we jointly modelled the CHEOPS photometry with the existing optical and near-infrared photometry from TESS, LBT, CFHT, and Spitzer. Our modelling has led to a self-consistent dayside spectrum for KELT-1b covering the CHEOPS, TESS, H, Ks, and Spitzer IRAC 3.6 and 4.5 µm bands, where our TESS, H, Ks, and Spitzer band estimates largely agree with the previous studies. However, we discovered a strong discrepancy between the CHEOPS and TESS bands. The CHEOPS observations yield a higher photometric precision than the TESS observations, but they do not show a significant eclipse signal, while a deep eclipse is detected in the TESS band. The derived TESS geometric albedo of 0.36−0.13+0.12 is difficult to reconcile with a CHEOPS geometric albedo that is consistent with zero because the two passbands have considerable overlap. Variability in cloud cover caused by the transport of transient nightside clouds to the dayside could provide an explanation for reconciling the TESS and CHEOPS geometric albedos, but this hypothesis needs to be tested by future observations.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Instituto de Astrofísica de Canarias, Universidad de La Laguna, University of St. Andrews, Université de Genève, Universität Bern, Università degli Studi di Torino, Aix-Marseille Université, National Institute for Earth Sciences & Astronomy (INSU-CNRS), University of Warwick, Universidade do Porto, Österreichische Akademie der Wissenschaften (ÖAW), INAF-Osservatorio Astrofisico di Catania, Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), Admatis, European Space Astronomy Centre (ESA), University of Grenoble Alpes, Stockholm University, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université de Paris, Science and Operations Department - Science Division (SCI-SC), Lund University, Université de Liège, Osservatorio Astronomico, Leiden University, Chalmers University of Technology, 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, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Technische Universität Berlin, Freie Universität Berlin (FU)
- Journal
- Astronomy and Astrophysics
- Volume
- 668
- No. of pages
- 23
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361/202244117
- Publication date
- 12-2022
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy, 103004 Astrophysics
- Keywords
- ASJC Scopus subject areas
- Astronomy and Astrophysics, Space and Planetary Science
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/cheops-finds-kelt1b-darker-than-expected-in-visible-light(6aa19e56-d51a-4c5c-8f53-725f7b5d0b63).html