CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side
Artikel i vetenskaplig tidskrift, 2024
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 (Ïμ = 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.
Planets and satellites: gaseous planets
Planets and satellites: individual: KELT-20 b
Techniques: photometric
Planets and satellites: individual: MASCARA-2 b
Planets and satellites: atmospheres
Författare
V. Singh
Istituto nazionale di astrofisica (INAF)
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
A. M.S. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
P. E. Cubillos
Institut fur Weltraumforschung
Istituto nazionale di astrofisica (INAF)
M. Lendl
Université de Genève
N. Billot
Université de Genève
A. Fortier
Universität Bern
D. Queloz
University of Cambridge
Eidgenössische Technische Hochschule Zürich (ETH)
S. G. Sousa
Universidade do Porto
Szilard Csizmadia
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
A. Brandeker
Stockholms universitet
L. Carone
Institut fur Weltraumforschung
T.G. Wilson
The University of Warwick
B. Akinsanmi
Université de Genève
J. A. Patel
Stockholms universitet
A. Krenn
Institut fur Weltraumforschung
O. Demangeon
Universidade do Porto
G. Bruno
Istituto nazionale di astrofisica (INAF)
I. Pagano
Istituto nazionale di astrofisica (INAF)
M.J. Hooton
University of Cambridge
J. Cabrera
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
N. C. Santos
Universidade do Porto
Y. Alibert
Universität Bern
R. Alonso
Universidad de la Laguna
Instituto de Astrofísica de Canarias
J. Asquier
European Space Research and Technology Centre (ESA ESTEC)
T. Bárczy
Admatis
D. Barrado Navascues
Centro de Astrobiologia (CAB)
S.C.C. Barros
Universidade do Porto
W. Baumjohann
Institut fur Weltraumforschung
M. Beck
Université de Genève
T. Beck
Universität Bern
W. Benz
Universität Bern
M. Bergomi
Istituto nazionale di astrofisica (INAF)
A. Bonfanti
Institut fur Weltraumforschung
X. Bonfils
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
L. Borsato
Istituto nazionale di astrofisica (INAF)
C. Broeg
Universität Bern
S. Charnoz
Institut de Physique du Globe de Paris
A. Collier Cameron
University of St Andrews
M. B. Davies
Lunds universitet
M. Deleuil
Laboratoire d'Astrophysique de Marseille
A. Deline
Université de Genève
L. Delrez
Universite de Liège
B.O. Demory
Universität Bern
D. Ehrenreich
Université de Genève
Anders Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Universiteit Leiden
D. Gandolfi
Universita degli Studi di Torino
Michaël Gillon
Universite de Liège
M. Gudel
Universität Wien
Maximilian N. Günther
European Space Research and Technology Centre (ESA ESTEC)
J. V. Harre
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
A. Heitzmann
Université de Genève
Ch. Helling
Institut fur Weltraumforschung
Technische Universität Graz
S. Hoyer
Laboratoire d'Astrophysique de Marseille
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. L. Kiss
Eötvös Loránd University (ELTE)
Magyar Tudomanyos Akademia
K. W.F. Lam
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Laskar
Observatoire de Paris
A. L. des Etangs
Centre national de la recherche scientifique (CNRS)
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
H. Mischler
Universität Bern
C. Mordasini
Universität Bern
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholms universitet
R. Ottensamer
Universität Wien
Enric Palle
Instituto de Astrofísica de Canarias
Universidad de la Laguna
G. Peter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Giampaolo P. Piotto
Università di Padova
Istituto nazionale di astrofisica (INAF)
D. Pollacco
The University of Warwick
R. Ragazzoni
Università di Padova
Istituto nazionale di astrofisica (INAF)
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Technische Universität Berlin
Freie Universität Berlin
I. Ribas
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
S. Salmon
Université de Genève
D. Segransan
Université de Genève
A.E. Simon
Universität Bern
M. Stalport
Universite de Liège
M. Steinberger
Institut fur Weltraumforschung
G.M. Szabó
Eötvös Loránd University (ELTE)
Nicolas Thomas
Universität Bern
S. Udry
Université de Genève
B. Ulmer
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
V. Van Grootel
Universite de Liège
J. Venturini
Université de Genève
E. Villaver
Universidad de la Laguna
Instituto de Astrofísica de Canarias
N. A. Walton
University of Cambridge
Tiziano Zingales
Università di Padova
Istituto nazionale di astrofisica (INAF)
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 683 A1Exoplaneter från rymden - CHEOPS och PLATO, ESA's nästa två missioner
Rymdstyrelsen (174/18), 2017-01-01 -- 2022-12-31.
Exoplaneter från rymden - CHEOPS och PLATO, ESA's nästa två rymdteleskop (fas 2)
Rymdstyrelsen (65/19), 2020-01-01 -- 2022-12-31.
Rymdstyrelsen (177/19), 2020-01-01 -- 2022-12-31.
Ämneskategorier
Astronomi, astrofysik och kosmologi
Infrastruktur
Onsala rymdobservatorium
DOI
10.1051/0004-6361/202347533