Refined parameters of the HD 22946 planetary system and the true orbital period of planet d
Artikel i vetenskaplig tidskrift, 2023
Context. Multi-planet systems are important sources of information regarding the evolution of planets. However, the long-period planets in these systems often escape detection. These objects in particular may retain more of their primordial characteristics compared to close-in counterparts because of their increased distance from the host star. HD 22946 is a bright (G = 8.13 mag) late F-type star around which three transiting planets were identified via Transiting Exoplanet Survey Satellite (TESS) photometry, but the true orbital period of the outermost planet d was unknown until now. Aims. We aim to use the Characterising Exoplanet Satellite (CHEOPS) space telescope to uncover the true orbital period of HD 22946d and to refine the orbital and planetary properties of the system, especially the radii of the planets. Methods. We used the available TESS photometry of HD 22946 and observed several transits of the planets b, c, and d using CHEOPS. We identified two transits of planet d in the TESS photometry, calculated the most probable period aliases based on these data, and then scheduled CHEOPS observations. The photometric data were supplemented with ESPRESSO (Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations) radial velocity data. Finally, a combined model was fitted to the entire dataset in order to obtain final planetary and system parameters. Results. Based on the combined TESS and CHEOPS observations, we successfully determined the true orbital period of the planet d to be 47.42489 ± 0.00011 days, and derived precise radii of the planets in the system, namely 1.362 ± 0.040 R, 2.328 ± 0.039 R, and 2.607 ± 0.060 R for planets b, c, and d, respectively. Due to the low number of radial velocities, we were only able to determine 3σ upper limits for these respective planet masses, which are 13.71 M, 9.72 M, and 26.57 M. We estimated that another 48 ESPRESSO radial velocities are needed to measure the predicted masses of all planets in HD 22946. We also derived stellar parameters for the host star. Conclusions. Planet c around HD 22946 appears to be a promising target for future atmospheric characterisation via transmission spectroscopy. We can also conclude that planet d, as a warm sub-Neptune, is very interesting because there are only a few similar confirmed exoplanets to date. Such objects are worth investigating in the near future, for example in terms of their composition and internal structure.
Methods: observational
Techniques: photometric
Planets and satellites: fundamental parameters
Författare
Z. Garai
Eötvös Loránd University (ELTE)
Slovak Academy of Sciences
H. P. Osborn
Massachusetts Institute of Technology (MIT)
Universität Bern
D. Gandolfi
Universita degli Studi di Torino
A. Brandeker
Stockholms universitet
S. G. Sousa
Universidade do Porto
M. Lendl
Université de Genève
A. Bekkelien
Université de Genève
C. Broeg
Universität Bern
A. Collier Cameron
University of St Andrews
J. A. Egger
Universität Bern
M.J. Hooton
University of Cambridge
Universität Bern
Y. Alibert
Universität Bern
L. Delrez
Universite de Liège
L. Fossati
Institut fur Weltraumforschung
S. Salmon
Université de Genève
T.G. Wilson
University of St Andrews
A. Bonfanti
Institut fur Weltraumforschung
A. Tuson
University of Cambridge
S. Ulmer-Moll
Universität Bern
Université de Genève
L. M. Serrano
Universita degli Studi di Torino
L. Borsato
Istituto nazionale di astrofisica (INAF)
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)
J. Asquier
European Space Research and Technology Centre (ESA ESTEC)
D. Barrado
European Space Astronomy Centre (ESAC)
S.C.C. Barros
Universidade do Porto
T. Bárczy
Admatis
W. Baumjohann
Institut fur Weltraumforschung
M. Beck
Université de Genève
T. Beck
Universität Bern
W. Benz
Universität Bern
N. Billot
Université de Genève
F. Biondi
Max-Planck-Gesellschaft
Istituto nazionale di astrofisica (INAF)
X. Bonfils
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
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
Istituto nazionale di astrofisica (INAF)
Institut fur Weltraumforschung
Melvyn B. Davies
Lunds universitet
M. Deleuil
Laboratoire d'Astrophysique de Marseille
O. Demangeon
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
Universidade do Porto
B.O. Demory
Universität Bern
D. Ehrenreich
Université de Genève
Anders Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Vincent Van Eylen
University College London (UCL)
A. Fortier
Universität Bern
Malcolm Fridlund
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Universiteit Leiden
Michaël Gillon
Universite de Liège
V. Van Grootel
Universite de Liège
M. Gudel
Universität Wien
Maximilian N. Günther
European Space Research and Technology Centre (ESA ESTEC)
S. Hoyer
Laboratoire d'Astrophysique de Marseille
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. Kiss
Magyar Tudomanyos Akademia
M. H. Kristiansen
Brorfelde Observatory
J. Laskar
Observatoire de Paris
A. L. des Etangs
Institut d 'Astrophysique de Paris
C. Lovis
Université de Genève
A. Luntzer
Universität Wien
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)
E. Palle
Instituto de Astrofísica de Canarias
Universidad de la Laguna
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
D. Queloz
Université de Genève
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
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Technische Universität Berlin
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)
D. Segransan
Université de Genève
A.E. Simon
Universität Bern
A. 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
J. Venturini
Université de Genève
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 674 A44Satellitstudier av exoplaneters mångfald
Rymdstyrelsen (174/18), 2019-02-04 -- 2023-08-01.
Ämneskategorier
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/202345943