55 Cancri e’s occultation captured with CHEOPS^★,★★

¹ Center for Space and Habitability, University of Bern, Gesellschaftsstrasse 6, 3012 Bern, Switzerland
e-mail: brice.demory@csh.unibe.ch
² Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
³ Aix Marseille Univ, CNRS, CNES, LAM, 38 rue Frédéric Joliot-Curie, 13388 Marseille, France
⁴ Astrobiology Research Unit, Université de Liège, Allée du 6 Août 19C, 4000 Liège, Belgium
⁵ Space sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, Allée du 6 Août 19C, 4000 Liège, Belgium
⁶ Department of Astronomy, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
⁷ Observatoire Astronomique de l’Université de Genève, Chemin Pegasi 51, 1290 Versoix, Switzerland
⁸ Instituto de Astrofísica e Ciencias do Espaco, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal
⁹ Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
¹⁰ Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria
¹¹ Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain
¹² Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
¹³ Institut de Ciencies de l’Espai (ICE, CSIC), Campus UAB, Can Magrans s/n, 08193 Bellaterra, Spain
¹⁴ Institut d’Estudis Espacials de Catalunya (IEEC), 08034 Barcelona, Spain
¹⁵ Admatis, 5. Kando Kalman Street, 3534 Miskolc, Hungary
¹⁶ Depto. de Astrofísica, Centro de Astrobiologia (CSIC-INTA), ESAC campus, 28692 Villanueva de la Canada (Madrid), Spain
¹⁷ Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
¹⁸ Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
¹⁹ Center for Space and Habitability, Gesellsschaftstrasse 6, 3012 Bern, Switzerland
²⁰ Institute of Optical Sensor Systems, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany
²¹ Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany
²² Université de Paris, Institut de physique du globe de Paris, CNRS, 75005 Paris, France
²³ Centre for Exoplanet Science, SUPA School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
²⁴ Almatech SA, EPFL Innovation Park, Bâtiment D, 1015 Lausanne, Switzerland
²⁵ Centre for Mathematical Sciences, Lund University, Box 118, 221 00 Lund, Sweden
²⁶ Observatoire Astronomique de l’Université de Genève, Chemin Pegasi 51, 1290 Versoix, Switzerland
²⁷ Centre Vie dans l’Univers, Faculté des sciences, Université de Genève, Quai Ernest-Ansermet 30, 1211 Genève 4, Switzerland
²⁸ Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands
²⁹ Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
³⁰ Dipartimento di Fisica, Universita degli Studi di Torino, via Pietro Giuria 1, 10125 Torino, Italy
³¹ University of Vienna, Department of Astrophysics, Türkenschanzstrasse 17, 1180 Vienna, Austria
³² Science and Operations Department – Science Division (SCI-SC), Directorate of Science, European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
³³ Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, 1121 Budapest, Konkoly Thege Miklos ut 15-17, Hungary
³⁴ ELTE Eötvös Loránd University, Institute of Physics, Pázmány Péter sétány 1/A, 1117, Hungary
³⁵ IMCCE, UMR8028 CNRS, Observatoire de Paris, PSL Univ., Sorbonne Univ., 77 av. Denfert-Rochereau, 75014 Paris, France
³⁶ Institut d’astrophysique de Paris, UMR7095 CNRS, Université Pierre et Marie Curie, 98 bis bvd. Arago, 75014 Paris, France
³⁷ Department of Astrophysics, University of Vienna, Tuerkenschanzstrasse 17, 1180 Vienna, Austria
³⁸ INAF, Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
³⁹ Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
⁴⁰ INAF, Osservatorio Astrofísico di Catania, Via S. Sofia 78, 95123 Catania, Italy
⁴¹ Dipartimento di Fisica e Astronomia “Galileo Galilei”, Universita degli Studi di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
⁴² ETH Zurich, Department of Physics, Wolfgang-Pauli-Strasse 2, 8093 Zurich, Switzerland
⁴³ Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, UK
⁴⁴ ESTEC, European Space Agency, 2201AZ, Noordwijk, NL, The Netherlands
⁴⁵ Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany
⁴⁶ Institut für Geologische Wissenschaften, Freie Universität Berlin, 12249 Berlin, Germany
⁴⁷ ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, 9700 Szombathely, Szent Imre h. u. 112, Hungary
⁴⁸ MTA-ELTE Exoplanet Research Group, 9700 Szombathely, Szent Imre h. u. 112, Hungary
⁴⁹ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK

Received: 6 September 2022
Accepted: 13 October 2022

Abstract

Past occultation and phase-curve observations of the ultra-short period super-Earth 55 Cnc e obtained at visible and infrared wavelengths have been challenging to reconcile with a planetary reflection and emission model. In this study, we analyse a set of 41 occultations obtained over a two-year timespan with the CHEOPS satellite. We report the detection of 55 Cnc e’s occultation with an average depth of 12 ± 3 ppm. We derive a corresponding 2σ upper limit on the geometric albedo of A_g < 0.55 once decontaminated from the thermal emission measured by Spitzer at 4.5 µm. CHEOPS’s photometric performance enables, for the first time, the detection of individual occultations of this super-Earth in the visible and identifies short-timescale photometric corrugations likely induced by stellar granulation. We also find a clear 47.3-day sinusoidal pattern in the time-dependent occultation depths that we are unable to relate to stellar noise, nor instrumental systematics, but whose planetary origin could be tested with upcoming JWST occultation observations of this iconic super-Earth.