TOI-5678b: A 48-day transiting Neptune-mass planet characterized with CHEOPS and HARPS
Artikel i vetenskaplig tidskrift, 2023
Context. A large sample of long-period giant planets has been discovered thanks to long-term radial velocity surveys, but only a few dozen of these planets have a precise radius measurement. Transiting gas giants are crucial targets for the study of atmospheric composition across a wide range of equilibrium temperatures and, more importantly, for shedding light on the formation and evolution of planetary systems. Indeed, compared to hot Jupiters, the atmospheric properties and orbital parameters of cooler gas giants are unaltered by intense stellar irradiation and tidal effects. Aims. We aim to identify long-period planets in the Transiting Exoplanet Survey Satellite (TESS) data as single or duo-transit events. Our goal is to solve the orbital periods of TESS duo-transit candidates with the use of additional space-based photometric observations and to collect follow-up spectroscopic observations in order to confirm the planetary nature and measure the mass of the candidates. Methods. We use the CHaracterising ExOPlanet Satellite (CHEOPS) to observe the highest-probability period aliases in order to discard or confirm a transit event at a given period. Once a period is confirmed, we jointly model the TESS and CHEOPS light curves along with the radial velocity datasets to measure the orbital parameters of the system and obtain precise mass and radius measurements. Results. We report the discovery of a long-period transiting Neptune-mass planet orbiting the G7-type star TOI-5678. Our spectroscopic analysis shows that TOI-5678 is a star with a solar metallicity. The TESS light curve of TOI-5678 presents two transit events separated by almost two years. In addition, CHEOPS observed the target as part of its Guaranteed Time Observation program. After four non-detections corresponding to possible periods, CHEOPS detected a transit event matching a unique period alias. Follow-up radial velocity observations were carried out with the ground-based high-resolution spectrographs CORALIE and HARPS. Joint modeling reveals that TOI-5678 hosts a 47.73 day period planet, and we measure an orbital eccentricity consistent with zero at 2σ. The planet TOI-5678 b has a mass of 20 ± 4 Earth masses (M) and a radius of 4.91 ± 0.08 R Using interior structure modeling, we find that TOI-5678 b is composed of a low-mass core surrounded by a large H/He layer with a mass of 3.2±1.7-1.3 M. Conclusions. TOI-5678 b is part of a growing sample of well-characterized transiting gas giants receiving moderate amounts of stellar insolation (11 S). Precise density measurement gives us insight into their interior composition, and the objects orbiting bright stars are suitable targets to study the atmospheric composition of cooler gas giants.
Planets and satellites: gaseous planets
Planets and satellites: detection
Planets and satellites: individual: TOI-5678
Methods: data analysis
Författare
S. Ulmer-Moll
Université de Genève
Universität Bern
H. P. Osborn
Massachusetts Institute of Technology (MIT)
Universität Bern
A. Tuson
University of Cambridge
J. A. Egger
Universität Bern
M. Lendl
Université de Genève
P. Maxted
Keele University
A. Bekkelien
Université de Genève
A.E. Simon
Universität Bern
G. Olofsson
Stockholms universitet
V. Adibekyan
Universidade do Porto
Y. Alibert
Universität Bern
A. Bonfanti
Institut fur Weltraumforschung
F. Bouchy
Université de Genève
A. Brandeker
Stockholms universitet
Malcolm Fridlund
Universiteit Leiden
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
D. Gandolfi
Universita degli Studi di Torino
C. Mordasini
Universität Bern
Carina Persson
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
S. Salmon
Université de Genève
L. M. Serrano
Universita degli Studi di Torino
S. G. Sousa
Universidade do Porto
T.G. Wilson
University of St Andrews
M. Rieder
Universität Bern
J. Hasiba
Institut fur Weltraumforschung
J. Asquier
European Space Research and Technology Centre (ESA ESTEC)
D. Sicilia
Istituto nazionale di astrofisica (INAF)
I. Walter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
R. Alonso
Universidad de la Laguna
Instituto de Astrofísica de Canarias
G. Anglada
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
D. Barrado
European Space Astronomy Centre (ESAC)
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
T. Bárczy
Admatis
J. Cabrera
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
S. Charnoz
Institut de Physique du Globe de Paris
M. Cointepas
Université de Genève
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
A. Collier Cameron
University of St Andrews
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
A. Deline
Université de Genève
L. Delrez
Universite de Liège
O. Demangeon
Universidade do Porto
B.O. Demory
Universität Bern
X. Dumusque
Université de Genève
D. Ehrenreich
Université de Genève
N. L. Eisner
Flatiron Institute
Anders Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
A. Fortier
Universität Bern
L. Fossati
Institut fur Weltraumforschung
Michaël Gillon
Universite de Liège
N. Grieves
Université de Genève
M. Gudel
Universität Wien
J. Hagelberg
Université de Genève
R. Helled
Universität Zürich
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)
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)
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
J. F. Otegi
Université de Genève
R. Ottensammer
Universität Wien
I. Pagano
Istituto nazionale di astrofisica (INAF)
E. Palle
Instituto de Astrofísica de Canarias
G. Peter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Giampaolo P. Piotto
Istituto nazionale di astrofisica (INAF)
Università di Padova
Don L. Pollacco
The University of Warwick
A. Psaridi
Université de Genève
D. Queloz
Eidgenössische Technische Hochschule Zürich (ETH)
University of Cambridge
Roberto Ragazzoni
Università di Padova
Istituto nazionale di astrofisica (INAF)
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
Technische Universität Berlin
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
I. Ribas
Institut de Ciències de l'Espai (ICE) - CSIC
Institut d'Estudis Espacials de Catalunya (IEEC)
N. C. Santos
Universidade do Porto
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
A. M.S. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Manfred B. Steller
Institut fur Weltraumforschung
G.M. Szabó
Eötvös Loránd University (ELTE)
D. Segransan
Université de Genève
Nicolas Thomas
Universität Bern
S. Udry
Université de Genève
V. Van Grootel
Universite de Liège
J. Venturini
Université de Genève
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 674 A43Satellitstudier av exoplaneters mångfald
Rymdstyrelsen (174/18), 2019-02-04 -- 2023-08-01.
Ämneskategorier
Astronomi, astrofysik och kosmologi
Annan fysik
DOI
10.1051/0004-6361/202245478