Refining the properties of the TOI-178 system with CHEOPS and TESS
Artikel i vetenskaplig tidskrift, 2023
Context. The TOI-178 system consists of a nearby late K-dwarf transited by six planets in the super-Earth to mini-Neptune regime, with radii ranging from -1.1 to 2.9 R and orbital periods between 1.9 and 20.7 days. All planets but the innermost one form a chain of Laplace resonances. Mass estimates derived from a preliminary radial velocity (RV) dataset suggest that the planetary densities do not decrease in a monotonic way with the orbital distance to the star, contrary to what one would expect based on simple formation and evolution models. Aims. To improve the characterisation of this key system and prepare for future studies (in particular with JWST), we performed a detailed photometric study based on 40 new CHEOPS visits, one new TESS sector, and previously published CHEOPS, TESS, and NGTS data. Methods. First we updated the parameters of the host star using the new parallax from Gaia EDR3. We then performed a global analysis of the 100 transits contained in our data to refine the physical and orbital parameters of the six planets and study their transit timing variations (TTVs). We also used our extensive dataset to place constraints on the radii and orbital periods of potential additional transiting planets in the system. Results. Our analysis significantly refines the transit parameters of the six planets, most notably their radii, for which we now obtain relative precisions of -3%, with the exception of the smallest planet, b, for which the precision is 5.1%. Combined with the RV mass estimates, the measured TTVs allow us to constrain the eccentricities of planets c to g, which are found to be all below 0.02, as expected from stability requirements. Taken alone, the TTVs also suggest a higher mass for planet d than that estimated from the RVs, which had been found to yield a surprisingly low density for this planet. However, the masses derived from the current TTV dataset are very prior-dependent, and further observations, over a longer temporal baseline, are needed to deepen our understanding of this iconic planetary system.
Techniques: photometric
Stars: individual: TOI-178
Planetary systems
Författare
L. Delrez
Universite de Liège
A. Leleu
Universität Bern
Université de Genève
A. Brandeker
Stockholms universitet
Michaël Gillon
Universite de Liège
M.J. Hooton
Universität Bern
University of Cambridge
A. Collier Cameron
University of St Andrews
A. Deline
Université de Genève
A. Fortier
Universität Bern
D. Queloz
University of Cambridge
Eidgenössische Technische Hochschule Zürich (ETH)
A. Bonfanti
Institut fur Weltraumforschung
V. Van Grootel
Universite de Liège
T.G. Wilson
University of St Andrews
J. A. Egger
Universität Bern
Y. Alibert
Universität Bern
R. Alonso
Instituto de Astrofísica de Canarias
Universidad de la Laguna
G. Anglada
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
J. Asquier
European Space Research and Technology Centre (ESA ESTEC)
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
W. Benz
Universität Bern
N. Billot
Université de Genève
X. Bonfils
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
L. Borsato
Istituto nazionale di astrofisica (INAF)
C. Broeg
Universität Bern
M. Buder
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Cabrera
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
V. Cessa
Universität Bern
S. Charnoz
Institut de Physique du Globe de Paris
Szilard Csizmadia
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
P. E. Cubillos
Institut fur Weltraumforschung
Istituto nazionale di astrofisica (INAF)
Melvyn B. Davies
Lunds universitet
M. Deleuil
Laboratoire d'Astrophysique de Marseille
O. Demangeon
Universidade do Porto
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
Universiteit Leiden
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
D. Gandolfi
Universita degli Studi di Torino
M. Gudel
Universität Wien
J. Hasiba
Institut fur Weltraumforschung
S. Hoyer
Laboratoire d'Astrophysique de Marseille
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
Jon M. Jenkins
NASA Ames Research Center
L. Kiss
Magyar Tudomanyos Akademia
Eötvös Loránd University (ELTE)
J. Laskar
Observatoire de Paris
D. W. Latham
Harvard-Smithsonian Center for Astrophysics
A. L. des Etangs
Institut d 'Astrophysique de Paris
M. Lendl
Université de Genève
C. Lovis
Université de Genève
R. Luque
University of Chicago
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
C. Mordasini
Universität Bern
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholms universitet
R. Ottensamer
Universität Wien
I. Pagano
Istituto nazionale di astrofisica (INAF)
Enric Palle
Instituto de Astrofísica de Canarias
G. Peter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Giampaolo P. Piotto
Università di Padova
Istituto nazionale di astrofisica (INAF)
Don L. Pollacco
The University of Warwick
R. 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
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
George R. Ricker
Massachusetts Institute of Technology (MIT)
N. C. Santos
Universidade do Porto
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
S. Seager
Massachusetts Institute of Technology (MIT)
D. Segransan
Université de Genève
A.E. Simon
Universität Bern
A. M.S. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
S.G. Sousa
Universidade do Porto
Manfred B. Steller
Institut fur Weltraumforschung
G.M. Szabó
Eötvös Loránd University (ELTE)
Nicolas Thomas
Universität Bern
S. Udry
Université de Genève
Roland K. Vanderspek
Massachusetts Institute of Technology (MIT)
J. Venturini
Université de Genève
V. Viotto
Istituto nazionale di astrofisica (INAF)
N. A. Walton
University of Cambridge
J. N. Winn
Princeton University
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 678 A200Ämneskategorier
Subatomär fysik
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/202245479