CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side

Singh, V. and Scandariato, G. and Smith, A. M. S. and Cubillos, P. E. and Lendl, M. and Billot, N. and Fortier, A. and Queloz, D. and Sousa, S. G. and Csizmadia, Sz. and Brandeker, A. and Carone, L. and Wilson, T. G. and Akinsanmi, B. and Patel, J. A. and Krenn, A. and Demangeon, O. D. S. and Bruno, G. and Pagano, I. and Hooton, M. J. and Cabrera, J. and Santos, N. C. and Alibert, Y. and Alonso Sobrino, R. and Asquier, J. and Bàrczy, T. and Barrado Navascues, D. and Barros, S. C. C. and Baumjohann, W. and Beck, M. and Beck, T. and Benz, W. and Bergomi, M. and Bonfanti, A. and Bonfils, X. and Borsato, L. and Broeg, C. and Charnoz, S. and Cameron, A. Collier and Davies, M. B. and Deleuil, M. and Deline, A. and Delrez, L. and Demory, B. -O. and Ehrenreich, D. and Erikson, A. and Fossati, L. and Fridlund, M. and Gandolfi, D. and Gillon, M. and Güdel, M. and Günther, M. N. and Harre, J.-V. and Heitzmann, A. and Helling, Ch. and Hoyer, S. and Isaak, K. G. and Kiss, L. L. and Lam, K. W. F. and Laskar, J. and Lecavelier des Etangs, A. and Magrin, D. and Maxted, P. F. L. and Mischler, H. and Mordasini, C. and Nascimbeni, V. and Olofsson, G. and Ottensamer, R. and Palle, E. and Peter, G. and Piotto, G. and Pollacco, D. and Ragazzoni, R. and Rando, N. and Rauer, H. and Ribas, I. and Salmon, S. and Ségransan, D. and Simon, A. E. and Stalport, M. and Steinberger, M. and Szabó, Gy. M. and Thomas, N. and Udry, S. and Ulmer, B. and Van Grootel, V. and Venturini, J. and Villaver, E. and Walton, N. A. and Zingales, T. (2024) CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side. Astronomy and Astrophysics, 683, A1. EDP Sciences. doi: 10.1051/0004-6361/202347533. ISSN 0004-6361.

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Official URL: https://www.aanda.org/articles/aa/full_html/2024/03/aa47533-23/aa47533-23.html

Abstract

Context. Occultations are windows of opportunity to indirectly peek into the dayside atmosphere of exoplanets. High-precision transit events provide information on the spin-orbit alignment of exoplanets around fast-rotating hosts. Aims: We aim to precisely measure the planetary radius and geometric albedo of the ultra-hot Jupiter (UHJ) KELT-20 b along with the spin-orbit alignment of the system. Methods: We obtained optical high-precision transits and occultations of KELT-20 b using CHEOPS observations in conjunction with simultaneous TESS observations. We interpreted the occultation measurements together with archival infrared observations to measure the planetary geometric albedo and dayside temperatures. We further used the host star's gravity-darkened nature to measure the system's obliquity. Results: We present a time-averaged precise occultation depth of 82 ± 6 ppm measured with seven CHEOPS visits and 131−7+8 from the analysis of all available TESS photometry. Using these measurements, we precisely constrain the geometric albedo of KELT-20 b to 0.26 ± 0.04 and the brightness temperature of the dayside hemisphere to 2566−80+77 K. Assuming Lambertian scattering law, we constrain the Bond albedo to 0.36−0.05+0.04 along with a minimal heat transfer to the night side (ϵ = 0.14−0.10+0.13). Furthermore, using five transit observations we provide stricter constraints of 3 9 ± 1 1 deg on the sky-projected obliquity of the system. Conclusions: The aligned orbit of KELT-20 b is in contrast to previous CHEOPS studies that have found strongly inclined orbits for planets orbiting other A-type stars. The comparably high planetary geometric albedo of KELT-20 b corroborates a known trend of strongly irradiated planets being more reflective. Finally, we tentatively detect signs of temporal variability in the occultation depths, which might indicate variable cloud cover advecting onto the planetary day side.

Item URL in elib:

https://elib.dlr.de/203444/

Document Type:

Article

Title:

CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side

Authors:

Authors	Institution or Email of Authors	Author's ORCID iD	ORCID Put Code
Singh, V.	INAF, Osservatorio Astrofisico di Catania, Italy	UNSPECIFIED	UNSPECIFIED
Scandariato, G.	INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania, Italy	UNSPECIFIED	UNSPECIFIED
Smith, A. M. S.	UNSPECIFIED	https://orcid.org/0000-0002-2386-4341	UNSPECIFIED
Cubillos, P. E.	INAF, Osservatorio Astrofisico di Torino, Via Osservatorio, 20, 10025, Pino Torinese, To, Italy; Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042, Graz, Austria	UNSPECIFIED	UNSPECIFIED
Lendl, M.	Observatoire de Genève, Université de Genève, Chemin Pegasi, 51, 1290, Versoix, Switzerland	UNSPECIFIED	UNSPECIFIED
Billot, N.	Observatoire de Genève, University of Geneva, Switzerland	UNSPECIFIED	UNSPECIFIED
Fortier, A.	Physikalisches Institut, University of Bern, Bern, Switzerland	https://orcid.org/0000-0001-8450-3374	UNSPECIFIED
Queloz, D.	ETH Zurich, Department of Physics, Wolfgang-Pauli-Strasse 2, 8093, Zurich, Switzerland; Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, UK	UNSPECIFIED	UNSPECIFIED
Sousa, S. G.	Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762, Porto, Portugal	UNSPECIFIED	UNSPECIFIED
Csizmadia, Sz.	UNSPECIFIED	https://orcid.org/0000-0001-6803-9698	UNSPECIFIED
Brandeker, A.	Department of Astronomy , Stockholm University, SE-106 91 Stockholm, Sweden	UNSPECIFIED	UNSPECIFIED
Carone, L.	Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042, Graz, Austria	UNSPECIFIED	UNSPECIFIED
Wilson, T. G.	Centre for Exoplanet Science, SUPA School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK	UNSPECIFIED	UNSPECIFIED
Akinsanmi, B.	Observatoire Astronomique de l'Université de Genève, Chemin Pegasi 51, 1290, Versoix, Switzerland	UNSPECIFIED	UNSPECIFIED
Patel, J. A.	Department of Astronomy , Stockholm University, SE-106 91 Stockholm, Sweden	UNSPECIFIED	UNSPECIFIED
Krenn, A.	Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria	UNSPECIFIED	UNSPECIFIED
Demangeon, O. D. S.	Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762, Porto, Portugal	UNSPECIFIED	UNSPECIFIED
Bruno, G.	INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123, Catania, Italy	UNSPECIFIED	UNSPECIFIED
Pagano, I.	Istituto Nazionale di Astrofisica - Osservatorio Astrofisico di Catania	UNSPECIFIED	UNSPECIFIED
Hooton, M. J.	Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, UK; Physikalisches Institut, University of Bern, Gesellsschaftstrasse 6, 3012, Bern, Switzerland	https://orcid.org/0000-0003-0030-332X	UNSPECIFIED
Cabrera, J.	UNSPECIFIED	https://orcid.org/0000-0001-6653-5487	UNSPECIFIED
Santos, N. C.	Instituto de Astrofisica e Ciencias do Espaco, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal; Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua Campo Alegre, 4169-007 Porto, Portugal	UNSPECIFIED	UNSPECIFIED
Alibert, Y.	Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland	UNSPECIFIED	UNSPECIFIED
Alonso Sobrino, R.	Instituto de Astrofisica de Canarias (IAC), 38205, La Laguna, Tenerife, Spain; Departamento de Astrofisica, Universidad de La Laguna, 38206, La Laguna, Tenerife, Spain	UNSPECIFIED	UNSPECIFIED
Asquier, J.	ESTEC, European Space Agency, 2201AZ, Noordwijk, NL	UNSPECIFIED	UNSPECIFIED
Bàrczy, T.	Admatis, Miskolc, Hungary	UNSPECIFIED	UNSPECIFIED
Barrado Navascues, D.	Depto. de Astrofisica, Centro de Astrobiologia (CSIC-INTA), ESAC Campus, E-28692 Villanueva de la Cañada, Madrid, Spain	UNSPECIFIED	UNSPECIFIED
Barros, S. C. C.	Instituto de Astrofisica e Ciencias do Espaco, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal	https://orcid.org/0000-0003-2434-3625	UNSPECIFIED
Baumjohann, W.	Space Research Institute, Austrian Academy of Sciences, Graz, Austria	UNSPECIFIED	UNSPECIFIED
Beck, M.	Observatoire de Genève, University of Geneva, Switzerland	UNSPECIFIED	UNSPECIFIED
Beck, T.	Center for Space and Habitability, University of Bern, Gesellschaftsstraße 6, 3012, Bern, Switzerland	UNSPECIFIED	UNSPECIFIED
Benz, W.	Physikalisches Institut, Universität Bern, CH	UNSPECIFIED	UNSPECIFIED
Bergomi, M.	INAF - Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova, Italy	UNSPECIFIED	UNSPECIFIED
Bonfanti, A.	Space Research Institute, Austrian Academy of Sciences, Austria	UNSPECIFIED	UNSPECIFIED
Bonfils, X.	Institut de Planétologie et d'Astrophysique, University of Grenoble, France	UNSPECIFIED	UNSPECIFIED
Borsato, L.	Dipartimento di Fisica e Astronomia, Universita degli Studi di Padova, via Marzolo 8, 35131 Padova, Italy	https://orcid.org/0000-0001-8627-9628	UNSPECIFIED
Broeg, C.	Physikalisches Institut, University of Bern, Bern, Switzerland	UNSPECIFIED	UNSPECIFIED
Charnoz, S.	Université de Paris, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France	UNSPECIFIED	UNSPECIFIED
Cameron, A. Collier	Centre for Exoplanet Science, SUPA School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK	UNSPECIFIED	UNSPECIFIED
Davies, M. B.	Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, 22100, Lund, Sweden	UNSPECIFIED	UNSPECIFIED
Deleuil, M.	Aix-Marseille Universite, CNRS, CNES, LAM, Marseille, France	UNSPECIFIED	UNSPECIFIED
Deline, A.	Observatoire de Genève, University of Geneva, Switzerland	UNSPECIFIED	UNSPECIFIED
Delrez, L.	Institut d Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout, 17, Bat. B5C, Liege 1, Belgium	UNSPECIFIED	UNSPECIFIED
Demory, B. -O.	Center for Space and Habitability, Gesellsschaftstrasse 6, 3012, Bern, Switzerland	UNSPECIFIED	UNSPECIFIED
Ehrenreich, D.	Observatoire de Genève, University of Geneva, Switzerland	https://orcid.org/0000-0001-9704-5405	UNSPECIFIED
Erikson, A.	UNSPECIFIED	UNSPECIFIED	UNSPECIFIED
Fossati, L.	Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042, Graz, Austria	UNSPECIFIED	UNSPECIFIED
Fridlund, M.	Department of Space, Earth and Environment, Chalmers University of Technology, Onsala Space Observatory, 439 92, Onsala, Sweden; Leiden Observatory, Leiden University, 2333CA, Leiden, The Netherlands	UNSPECIFIED	UNSPECIFIED
Gandolfi, D.	Dipartimento di Fisica, Universita di Torino	UNSPECIFIED	UNSPECIFIED
Gillon, M.	Astrobiology Research Unit, Université de Liège, 19C Allée du 6 Août, 4000, Liège, Belgium	UNSPECIFIED	UNSPECIFIED
Güdel, M.	University of Vienna, Department of Astrophysics, Türkenschanzstrasse 17, 1180, Vienna, Austria	UNSPECIFIED	UNSPECIFIED
Günther, M. N.	European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ, Noordwijk, The Netherlands	UNSPECIFIED	UNSPECIFIED
Harre, J.-V.	UNSPECIFIED	UNSPECIFIED	UNSPECIFIED
Heitzmann, A.	Observatoire Astronomique de l'Université de Genève, Chemin Pegasi 51, 1290, Versoix, Switzerland	UNSPECIFIED	UNSPECIFIED
Helling, Ch.	Space Research Institute, Austrian Academy of Sciences, Graz, Austria	UNSPECIFIED	UNSPECIFIED
Hoyer, S.	Aix Marseille Univ, CNRS, CNES, LAM, F-13013 Marseille, France	UNSPECIFIED	UNSPECIFIED
Isaak, K. G.	ESA/ESTEC, Niederlande	UNSPECIFIED	UNSPECIFIED
Kiss, L. L.	Konkoly Observatory, Research Centre for Astronomy and Earth, Budapest, Hungary	UNSPECIFIED	UNSPECIFIED
Lam, K. W. F.	UNSPECIFIED	https://orcid.org/0000-0002-9910-6088	UNSPECIFIED
Laskar, J.	IMCCE, UMR8028 CNRS, Observatoire de Paris, PSL Univ.,Sorbonne Univ., 77 av. Denfert-Rochereau, 75014 Paris, France	UNSPECIFIED	UNSPECIFIED
Lecavelier des Etangs, A.	Institut d Astrophysique de Paris, CNRS, UMR 7095 & Sorbonne Universites, UPMC Paris 6, 98 bis bd Arago, 75014 Paris, France	UNSPECIFIED	UNSPECIFIED
Magrin, D.	INAF,OsservatorioAstronomicodiPadova,Vicolodell’Osservatorio 5, 35122 Padova, Italy	UNSPECIFIED	UNSPECIFIED
Maxted, P. F. L.	Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK	UNSPECIFIED	UNSPECIFIED
Mischler, H.	physics institute, space research & planetary sciences, university of bern, sidlerstr. 5, ch-3012 bern, switzerland	UNSPECIFIED	UNSPECIFIED
Mordasini, C.	Physikalisches Institut, University of Bern, Gesellschaftsstrasse 6, 3012, Bern, Switzerland	UNSPECIFIED	UNSPECIFIED
Nascimbeni, V.	INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania, Italy	UNSPECIFIED	UNSPECIFIED
Olofsson, G.	Department of Astronomy, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden	UNSPECIFIED	UNSPECIFIED
Ottensamer, R.	Dept. of Astrophysics, University of Vienna, Austria	UNSPECIFIED	UNSPECIFIED
Palle, E.	Instituto de Astrofısica de Canarias, 38205 La Laguna, Tenerife, Spain	UNSPECIFIED	UNSPECIFIED
Peter, G.	UNSPECIFIED	https://orcid.org/0000-0001-6101-2513	UNSPECIFIED
Piotto, G.	INAF – Osservatorio Astronomico di Padova, vicolo dell Osservatorio 5, 35122 Padova, Italy	UNSPECIFIED	UNSPECIFIED
Pollacco, D.	Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK; Centre for Exoplanets and Habitability, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK	UNSPECIFIED	UNSPECIFIED
Ragazzoni, R.	Dipartimento di Fisica e Astronomia, Universita degli Studi di Padova, Vicolo dell Osservatorio 3, 35122 Padova, Italy	UNSPECIFIED	UNSPECIFIED
Rando, N.	ESA/ESTEC, Niederlande	UNSPECIFIED	UNSPECIFIED
Rauer, H.	UNSPECIFIED	UNSPECIFIED	UNSPECIFIED
Ribas, I.	Institut de Ciències de l’Espai (CSIC), Campus UAB, c/ de Can Magrans s/n, Barcelona, Spain; Institut d’Estudis Espacials de Catalunya, Barcelona, Spain	UNSPECIFIED	UNSPECIFIED
Salmon, S.	STAR, Université de Liège, Belgium	UNSPECIFIED	UNSPECIFIED
Ségransan, D.	Geneva Observatory, University of Geneva, Chemin Pegasi 51, CH-1290 Versoix, Switzerland	UNSPECIFIED	UNSPECIFIED
Simon, A. E.	Center for Space and Habitability, University of Bern, Switzerland	UNSPECIFIED	UNSPECIFIED
Stalport, M.	Geneva Observatory, University of Geneva, Chemin des Mailettes 51, 1290, Versoix, Switzerland	UNSPECIFIED	UNSPECIFIED
Steinberger, M.	Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, A-8042 Graz, Austria	UNSPECIFIED	UNSPECIFIED
Szabó, Gy. M.	ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, 9700, Szombathely, Szent Imre h. u. 112, Hungary ; MTA-ELTE Exoplanet Research Group, 9700, Szombathely, Szent Imre h. u. 112, Hungary	UNSPECIFIED	UNSPECIFIED
Thomas, N.	Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland	UNSPECIFIED	UNSPECIFIED
Udry, S.	Observatoire de Genève, Université de Genève, Chemin Pegasi, 51, 1290, Versoix, Switzerland	UNSPECIFIED	UNSPECIFIED
Ulmer, B.	Institute of Optical Sensor Systems, German Aerospace Center (DLR), Rutherfordstrasse 2, 12489, Berlin, Germany	UNSPECIFIED	UNSPECIFIED
Van Grootel, V.	Space sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, Allée du 6 Août 19C, 4000 Liège, Belgium	UNSPECIFIED	UNSPECIFIED
Venturini, J.	Observatoire Astronomique de l'Université de Genève, Chemin Pegasi 51, 1290, Versoix, Switzerland	UNSPECIFIED	UNSPECIFIED
Villaver, E.	Instituto de Astrofisica de Canarias, Via Lactea s/n, 38200, La Laguna, Tenerife, Spain; Departamento de Astrofisica, Universidad de La Laguna, Astrofisico Francisco Sanchez s/n, 38206, La Laguna, Tenerife, Spain	UNSPECIFIED	UNSPECIFIED
Walton, N. A.	Institute of Astronomy, University of Cambridge, Cambridge, UK	UNSPECIFIED	UNSPECIFIED
Zingales, T.	Dipartimento di Fisica e Astronomia "Galileo Galilei", Universita degli Studi di Padova, Vicolo dell'Osservatorio 3, 35122, Padova, Italy; INAF, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122, Padova, Italy	UNSPECIFIED	UNSPECIFIED

Date:

2024

Journal or Publication Title:

Astronomy and Astrophysics

Refereed publication:

Yes

Open Access:

Yes

Gold Open Access:

In SCOPUS:

Yes

In ISI Web of Science:

Yes

Volume:

683

DOI:

10.1051/0004-6361/202347533

Page Range:

Publisher:

EDP Sciences

ISSN:

0004-6361

Status:

Published

Keywords:

techniques: photometric, planets and satellites: atmospheres, planets and satellites: gaseous planets, planets and satellites: individual: KELT-20 b, planets and satellites: individual: MASCARA-2 b

HGF - Research field:

Aeronautics, Space and Transport

HGF - Program:

Space

HGF - Program Themes:

Space Exploration

DLR - Research area:

Raumfahrt

DLR - Program:

R EW - Space Exploration

DLR - Research theme (Project):

R - CHEOPS Science, R - Project CHEOPS

Location:

Berlin-Adlershof

Institutes and Institutions:

Institute of Planetary Research > Extrasolar Planets and Atmospheres
Institute of Planetary Research > Leitungsbereich PF
Institute of Optical Sensor Systems > Space Instruments

Deposited By:

Smith, Dr Alexis M S

Deposited On:

25 Mar 2024 14:35

Last Modified:

17 Jun 2024 13:58

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