CHEOPS finds KELT-1b darker than expected in visible light: Discrepancy between the CHEOPS and TESS eclipse depths
Artikel i vetenskaplig tidskrift, 2022
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.
Stars: atmospheres
Planetary systems
Stars: individual: KELT-1
Methods: observational
Brown dwarfs
Författare
H. Parviainen
Instituto de Astrofísica de Canarias
Universidad de la Laguna
T.G. Wilson
University of St Andrews
M. Lendl
Université de Genève
D. Kitzmann
Universität Bern
Enric Palle
Universidad de la Laguna
Instituto de Astrofísica de Canarias
L. M. Serrano
Universita degli Studi di Torino
E. Meier Valdes
Universität Bern
W. Benz
Universität Bern
A. Deline
Université de Genève
D. Ehrenreich
Université de Genève
P. Guterman
Laboratoire d'Astrophysique de Marseille
CS20330
Kevin Heng
Universität Bern
The University of Warwick
O. Demangeon
Universidade do Porto
A. Bonfanti
Institut fur Weltraumforschung
S. Salmon
Université de Genève
V. Singh
Istituto nazionale di astrofisica (INAF)
N. C. Santos
Universidade do Porto
S.G. Sousa
Universidade do Porto
Y. Alibert
Universität Bern
R. Alonso
Universidad de la Laguna
Instituto de Astrofísica de Canarias
G. Anglada
Consejo Superior de Investigaciones Científicas (CSIC)
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
T. Bárczy
Admatis
D. Barrado
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
N. Billot
Université de Genève
X. Bonfils
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
A. Brandeker
Stockholms universitet
C. Broeg
Universität Bern
J. Cabrera
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
S. Charnoz
Institut de Physique du Globe de Paris
A. Collier Cameron
University of St Andrews
C. Corral Van Damme
European Space Research and Technology Centre (ESA ESTEC)
Szilard Csizmadia
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
M. B. Davies
Lunds universitet
M. Deleuil
Laboratoire d'Astrophysique de Marseille
L. Delrez
Universite de Liège
B.O. Demory
Universität Bern
Anders Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Farinato
Istituto nazionale di astrofisica (INAF)
A. Fortier
Universität Bern
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
S. Hoyer
Laboratoire d'Astrophysique de Marseille
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. Kiss
Magyar Tudomanyos Akademia
Eötvös Loránd University (ELTE)
E. Kopp
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Laskar
Observatoire de Paris
A. L. des Etangs
Institut d 'Astrophysique de Paris
C. Lovis
Université de Genève
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
M. Mecina
Universität Wien
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholms universitet
R. Ottensamer
Universität Wien
I. Pagano
Istituto nazionale di astrofisica (INAF)
G. Peter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
D. Piazza
Universität Bern
Giampaolo P. Piotto
Università di Padova
Istituto nazionale di astrofisica (INAF)
Don L. Pollacco
The University of Warwick
D. Queloz
Eidgenössische Technische Hochschule Zürich (ETH)
University of Cambridge
Roberto Ragazzoni
Istituto nazionale di astrofisica (INAF)
Università di Padova
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
Technische Universität Berlin
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Freie Universität Berlin
I. Ribas
Consejo Superior de Investigaciones Científicas (CSIC)
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
Université de Genève
A.E. Simon
Universität Bern
Alexis M. S. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Manfred B. Steller
Institut fur Weltraumforschung
G.M. Szabó
Eötvös Loránd University (ELTE)
Nicolas Thomas
Universität Bern
S. Udry
Université de Genève
V. Van Grootel
Universite de Liège
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 668 A93Ämneskategorier (SSIF 2011)
Meteorologi och atmosfärforskning
Astronomi, astrofysik och kosmologi
Geofysik
DOI
10.1051/0004-6361/202244117