TOI-1055 b: Neptunian planet characterised with HARPS, TESS, and CHEOPS
Journal article, 2023
Context. TOI-1055 is a Sun-like star known to host a transiting Neptune-sized planet on a 17.5-day orbit (TOI-1055 b). Radial velocity (RV) analyses carried out by two independent groups using nearly the same set of HARPS spectra have provided measurements of planetary masses that differ by ∼2σ. Aims. Our aim in this work is to solve the inconsistency in the published planetary masses by significantly extending the set of HARPS RV measurements and employing a new analysis tool that is able to account and correct for stellar activity. Our further aim was to improve the precision on measurements of the planetary radius by observing two transits of the planet with the CHEOPS space telescope. Methods. We fit a skew normal function to each cross correlation function extracted from the HARPS spectra to obtain RV measurements and hyperparameters to be used for the detrending. We evaluated the correlation changes of the hyperparameters along the RV time series using the breakpoint technique. We performed a joint photometric and RV analysis using a Markov chain Monte Carlo scheme to simultaneously detrend the light curves and the RV time series. Results. We firmly detected the Keplerian signal of TOI-1055 b, deriving a planetary mass of Mb = 20.4-2.5+2.6 MO (∼12%). This value is in agreement with one of the two estimates in the literature, but it is significantly more precise. Thanks to the TESS transit light curves combined with exquisite CHEOPS photometry, we also derived a planetary radius of Rb = 3.490-0.064+0.070 RO (∼1.9%). Our mass and radius measurements imply a mean density of ρb = 2.65-0.35+0.37 g cm-3 (∼14%). We further inferred the planetary structure and found that TOI-1055 b is very likely to host a substantial gas envelope with a mass of 0.41-0.20+0.34 MO and a thickness of 1.05-0.29+0.30 RO. Conclusions. Our RV extraction combined with the breakpoint technique has played a key role in the optimal removal of stellar activity from the HARPS time series, enabling us to solve the tension in the planetary mass values published so far for TOI-1055 b.
Techniques: photometric
Planets and satellites: fundamental parameters
Stars: fundamental parameters
Techniques: radial velocities
Author
A. Bonfanti
Institut fur Weltraumforschung
D. Gandolfi
University of Turin
J. A. Egger
University of Bern
L. Fossati
Institut fur Weltraumforschung
J. Cabrera
German Aerospace Center (DLR)
A. Krenn
Institut fur Weltraumforschung
Y. Alibert
University of Bern
W. Benz
University of Bern
N. Billot
University of Geneva
H.-G. Florén
Stockholm University
M. Lendl
University of Geneva
V. Adibekyan
University of Porto
S. Salmon
University of Geneva
N. C. Santos
University of Porto
S. G. Sousa
University of Porto
T. G. Wilson
University of St Andrews
O. Barragán
University of Oxford
A. Collier Cameron
University of St Andrews
L. Delrez
University of Liège
M. Esposito
Thüringer Landessternwarte Tautenburg
E. Goffo
University of Turin
Thüringer Landessternwarte Tautenburg
H. L.M. Osborne
University College London (UCL)
H. P. Osborn
University of Bern
Massachusetts Institute of Technology (MIT)
L. M. Serrano
University of Turin
Vincent Van Eylen
University College London (UCL)
Javier Alarcon
European Southern Observatory Santiago
R. Alonso
University of La Laguna
Instituto de Astrofísica de Canarias
G. Anglada
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
T. Bárczy
Admatis
D. Barrado Navascues
Centro de Astrobiologia (CAB)
S. C.C. Barros
University of Porto
W. Baumjohann
Institut fur Weltraumforschung
M. Beck
University of Geneva
T. Beck
University of Bern
Megan Bedell
Flatiron Institute
X. Bonfils
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
L. Borsato
Istituto nazionale di astrofisica (INAF)
A. Brandeker
Stockholm University
C. Broeg
University of Bern
S. Charnoz
Institut de Physique du Globe de Paris
C. Corral Van Damme
European Space Research and Technology Centre (ESA ESTEC)
Szilard Csizmadia
German Aerospace Center (DLR)
P. E. Cubillos
Istituto nazionale di astrofisica (INAF)
Institut fur Weltraumforschung
M. B. Davies
Lund University
M. Deleuil
Laboratoire d'Astrophysique de Marseille
O. Demangeon
University of Porto
B.O. Demory
University of Bern
D. Ehrenreich
University of Geneva
Anders Erikson
German Aerospace Center (DLR)
A. Fortier
University of Bern
Malcolm Fridlund
Leiden University
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Michaël Gillon
University of Liège
M. Gudel
University of Vienna
S. Hoyer
Laboratoire d'Astrophysique de Marseille
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
F. Kerschbaum
University of Vienna
L.L. Kiss
Hungarian Academy of Sciences
Eötvös Loránd University (ELTE)
J. Laskar
Paris Observatory
A. L. des Etangs
Institut d 'Astrophysique de Paris
D. Lorenzo-Oliveira
University of Sao Paulo (USP)
Laboratorio Nacional de Astrofisica, Itajuba
C. Lovis
University of Geneva
D. Magrin
Istituto nazionale di astrofisica (INAF)
L. Marafatto
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
J. Meléndez
University of Sao Paulo (USP)
C. Mordasini
University of Bern
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholm University
R. Ottensamer
University of Vienna
I. Pagano
Istituto nazionale di astrofisica (INAF)
E. Palle
Instituto de Astrofísica de Canarias
G. Peter
German Aerospace Center (DLR)
D. Piazza
University of Bern
Giampaolo P. Piotto
Istituto nazionale di astrofisica (INAF)
University of Padua
D. Pollacco
The University of Warwick
D. Queloz
University of Cambridge
Swiss Federal Institute of Technology in Zürich (ETH)
Roberto Ragazzoni
University of Padua
Istituto nazionale di astrofisica (INAF)
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
Technische Universität Berlin
Freie Universität Berlin
German Aerospace Center (DLR)
I. Ribas
Institute of Space Sciences (ICE) - CSIC
Institute of Space Studies of Catalonia (IEEC)
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
University of Geneva
A.E. Simon
University of Bern
A. M.S. Smith
German Aerospace Center (DLR)
Manfred B. Steller
Institut fur Weltraumforschung
Gy M. Szabó
Eötvös Loránd University (ELTE)
N. Thomas
University of Bern
S. Udry
University of Geneva
B. Ulmer
German Aerospace Center (DLR)
V. Van Grootel
University of Liège
J. Venturini
University of Geneva
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 671 L8Subject Categories
Medical Laboratory and Measurements Technologies
Analytical Chemistry
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/202245607