The hot dayside and asymmetric transit of WASP-189 b seen by CHEOPS
Artikel i vetenskaplig tidskrift, 2020

The CHEOPS space mission dedicated to exoplanet follow-up was launched in December 2019, equipped with the capacity to perform photometric measurements at the 20 ppm level. As CHEOPS carries out its observations in a broad optical passband, it can provide insights into the reflected light from exoplanets and constrain the short-wavelength thermal emission for the hottest of planets by observing occultations and phase curves. Here, we report the first CHEOPS observation of an occultation, namely, that of the hot Jupiter WASP-189 b, a MP ≈ 2MJ planet orbiting an A-type star. We detected the occultation of WASP-189 b at high significance in individual measurements and derived an occultation depth of dF = 87.9 ± 4.3 ppm based on four occultations. We compared these measurements to model predictions and we find that they are consistent with an unreflective atmosphere heated to a temperature of 3435 ± 27 K, when assuming inefficient heat redistribution. Furthermore, we present two transits of WASP-189 b observed by CHEOPS. These transits have an asymmetric shape that we attribute to gravity darkening of the host star caused by its high rotation rate. We used these measurements to refine the planetary parameters, finding a ~25% deeper transit compared to the discovery paper and updating the radius of WASP-189 b to 1.619 ± 0.021RJ. We further measured the projected orbital obliquity to be λ = 86.4-4.4+2.9°, a value that is in good agreement with a previous measurement from spectroscopic observations, and derived a true obliquity of ψ = 85.4 ± 4.3°. Finally, we provide reference values for the photometric precision attained by the CHEOPS satellite: for the V = 6.6 mag star, and using a 1-h binning, we obtain a residual RMS between 10 and 17 ppm on the individual light curves, and 5.7 ppm when combining the four visits.

Techniques: photometric

Planets and satellites: individual: WASP-189 b

Planets and satellites: atmospheres

Författare

M. Lendl

Universite de Geneve

Szilard Csizmadia

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

A. Deline

Universite de Geneve

L. Fossati

Institut fur Weltraumforschung

D. Kitzmann

Universität Bern

Kevin Heng

Universität Bern

S. Hoyer

Laboratoire d'Astrophysique de Marseille

S. Salmon

Universite de Geneve

W. Benz

Universität Bern

C. Broeg

Universität Bern

D. Ehrenreich

Universite de Geneve

A. Fortier

Universität Bern

D. Queloz

Universite de Geneve

A. Bonfanti

Institut fur Weltraumforschung

A. Brandeker

Stockholms universitet

A. Collier Cameron

University of St Andrews

L. Delrez

Universite de Geneve

A. Garcia Munoz

Technische Universität Berlin

M.J. Hooton

Universität Bern

P. Maxted

Keele University

Brett M. Morris

Universität Bern

V. Van Grootel

Universite de Liège

T.G. Wilson

University of St Andrews

Y. Alibert

Universität Bern

R. Alonso

Instituto Astrofisico de Canarias

J. Asquier

European Space Research and Technology Centre (ESA ESTEC)

T. Bandy

Universität Bern

T. Bárczy

Admatis

D. Barrado

Centro de Astrobiologia (CAB)

S.C.C. Barros

Universidade do Porto

W. Baumjohann

Institut fur Weltraumforschung

M. Beck

Universite de Geneve

T. Beck

Universität Bern

A. Bekkelien

Universite de Geneve

M. Bergomi

Osservatorio Astronomico di Padova

N. Billot

Universite de Geneve

F. Biondi

Osservatorio Astronomico di Padova

X. Bonfils

Université Grenoble Alpes

V. Bourrier

Universite de Geneve

M.-D. Busch

Universität Bern

J. Cabrera

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

V. Cessa

Universität Bern

S. Charnoz

Institut de Physique du Globe de Paris

B. Chazelas

Universite de Geneve

C. Corral Van Damme

European Space Research and Technology Centre (ESA ESTEC)

Melvyn B. Davies

Lunds universitet

M. Deleuil

Laboratoire d'Astrophysique de Marseille

O. Demangeon

Laboratoire d'Astrophysique de Marseille

B.O. Demory

Universität Bern

Anders Erikson

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

J. Farinato

Osservatorio Astronomico di Padova

Malcolm Fridlund

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

Universiteit Leiden

D. Futyan

Universite de Geneve

D. Gandolfi

Istituto nazionale di astrofisica (INAF)

Michaël Gillon

Universite de Liège

P. Guterman

Laboratoire d'Astrophysique de Marseille

J. Hasiba

Institut fur Weltraumforschung

E. Hernandez

Universität Bern

K. Isaak

European Space Research and Technology Centre (ESA ESTEC)

L.L. Kiss

Magyar Tudomanyos Akademia

T. Kuntzer

Universite de Geneve

A. L. des Etangs

Institut d 'Astrophysique de Paris

T. Lüftinger

Universität Wien

J. Laskar

Observatoire de Paris

C. Lovis

Universite de Geneve

D. Magrin

Osservatorio Astronomico di Padova

L. Malvasio

Universität Bern

L. Marafatto

Osservatorio Astronomico di Padova

H. Michaelis

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

M. Munari

Osservatorio Astrofisico di Catania

Valerio Nascimbeni

Osservatorio Astronomico di Padova

G. Olofsson

Stockholms universitet

H. Ottacher

Institut fur Weltraumforschung

R. Ottensamer

Universität Wien

I. Pagano

Osservatorio Astrofisico di Catania

E. Palle

Instituto Astrofisico de Canarias

G. Peter

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

D. Piazza

Universität Bern

Giampaolo P. Piotto

Osservatorio Astronomico di Padova

Don L. Pollacco

The University of Warwick

F. Ratti

European Space Research and Technology Centre (ESA ESTEC)

H. Rauer

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Roberto Ragazzoni

Osservatorio Astronomico di Padova

N. Rando

European Space Research and Technology Centre (ESA ESTEC)

I. Ribas

Institut de Ciències de l'Espai (ICE) - CSIC

M. Rieder

Universität Bern

R. Rohlfs

Universite de Geneve

F. Safa

European Space Research and Technology Centre (ESA ESTEC)

N. C. Santos

Universidade do Porto

Gaetano Scandariato

Osservatorio Astrofisico di Catania

D. Segransan

Universite de Geneve

A.E. Simon

Universität Bern

V. Singh

Osservatorio Astrofisico di Catania

Alexis M. S. Smith

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

M. Sordet

Universite de Geneve

S.G. Sousa

Universidade do Porto

Manfred B. Steller

Institut fur Weltraumforschung

G.M. Szabó

Eötvös Loránd University (ELTE)

Nicolas Thomas

Universität Bern

M. Tschentscher

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

S. Udry

Universite de Geneve

V. Viotto

Osservatorio Astronomico di Padova

I. Walter

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

N. A. Walton

University of Cambridge

F. Wildi

Universite de Geneve

D. Wolter

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 643 202038677

Ämneskategorier

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik

Annan fysik

Fundament

Grundläggande vetenskaper

DOI

10.1051/0004-6361/202038677

Mer information

Senast uppdaterat

2020-12-02