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.

Planetary systems

Brown dwarfs

Methods: observational

Stars: individual: KELT-1

Stars: atmospheres

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

Instituto de Astrofísica de Canarias

Universidad de la Laguna

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

CS20330

Laboratoire d'Astrophysique de Marseille

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

Europeiska rymdorganisationen (ESA)

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

Europeiska rymdorganisationen (ESA)

L. Kiss

Eötvös Loránd University (ELTE)

Magyar Tudomanyos Akademia

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

Istituto nazionale di astrofisica (INAF)

Università di Padova

Don L. Pollacco

The University of Warwick

D. Queloz

University of Cambridge

Eidgenössische Technische Hochschule Zürich (ETH)

Roberto Ragazzoni

Istituto nazionale di astrofisica (INAF)

Università di Padova

N. Rando

Europeiska rymdorganisationen (ESA)

H. Rauer

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Technische Universität Berlin

Freie Universität Berlin

I. Ribas

Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

Consejo Superior de Investigaciones Científicas (CSIC)

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 A93

Ämneskategorier (SSIF 2011)

Meteorologi och atmosfärforskning

Astronomi, astrofysik och kosmologi

Geofysik

DOI

10.1051/0004-6361/202244117

Mer information

Senast uppdaterat

2025-04-23