The CHEOPS view of HD 95338b: Refined transit parameters, and a search for exomoons
Artikel i vetenskaplig tidskrift, 2025
Context. Despite the ever-increasing number of known exoplanets, no uncontested detections have been made of their satellites, known as exomoons. Aims. The quest to find exomoons is at the forefront of exoplanetary sciences. Certain space-born instruments are thought to be suitable for this purpose. We show the progress made with the CHaracterising ExOPlanets Satellite (CHEOPS) in this field using the HD 95338 planetary system. We present a novel methodology as an important step in the quest to find exomoons. Methods. We utilised ground-based spectroscopic data in combination with Gaia observations to obtain precise stellar parameters. These were then used as input in the analysis of the planetary transits observed by CHEOPS and the Transiting Exoplanet Survey Satellite (TESS). In addition, we searched for the signs of satellites primarily in the form of additional transits in the Hill sphere of the eccentric Neptune-sized planet HD 95338b in a sequential approach based on four CHEOPS visits. We also briefly explored the transit timing variations of the planet. Results. We present refined stellar and planetary parameters, narrowing down the uncertainty on the planet-to-star radius ratio by a factor of ten. We also pin down the ephemeris of HD 95338b. Using injection-and-retrieval tests, we show that a 5σ detection of an exomoon would be possible at RMoon = 0.8 R⊗ with the methodology presented here. Conclusions. We exclude the transit of an exomoon in the HD 95338 system with RMoon ≈ 0.6 R⊗ at the 1σ level. The algorithm used for finding the transit-like event can be used as a baseline for other similar targets, observed by CHEOPS or other missions.
Planets and satellites: individual: HD 95338b
Methods: data analysis
Techniques: photometric
Författare
Sz Kálmán
Eötvös Loránd University (ELTE)
Research Centre For Astronomy and Earth Sciences
Magyar Tudomanyos Akademia
A.E. Simon
Universität Bern
A. Deline
Université de Genève
Szilard Csizmadia
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
G.M. Szabó
Eötvös Loránd University (ELTE)
D. Ehrenreich
Université de Genève
T.G. Wilson
The University of Warwick
Maximilian N. Günther
Europeiska rymdorganisationen (ESA)
A. Heitzmann
Université de Genève
S.G. Sousa
Universidade do Porto
M. Farnir
Universite de Liège
A. Bonfanti
Institut fur Weltraumforschung
A. M.S. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
A. Pál
Magyar Tudomanyos Akademia
Eötvös Loránd University (ELTE)
Research Centre For Astronomy and Earth Sciences
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
V. Adibekyan
Universidade do Porto
A. Brandeker
Stockholms universitet
S. Charnoz
Institut de Physique du Globe de Paris
B. Akinsanmi
Université de Genève
S.C.C. Barros
Universidade do Porto
X. Song
Beijing University of Technology
Université de Genève
Y. Alibert
Universität Bern
Eötvös Loránd University (ELTE)
R. Alonso
Instituto de Astrofísica de Canarias
Universidad de la Laguna
T. Bárczy
Admatis
D. Barrado Navascues
Europeiska rymdorganisationen (ESA)
W. Baumjohann
Institut fur Weltraumforschung
W. Benz
Universität Bern
Eötvös Loránd University (ELTE)
N. Billot
Université de Genève
F. Biondi
Istituto nazionale di astrofisica (INAF)
Max-Planck-Gesellschaft
L. Borsato
Istituto nazionale di astrofisica (INAF)
C. Broeg
Eötvös Loránd University (ELTE)
Universität Bern
A. Collier Cameron
University of St Andrews
C. Corral Van Damme
Europeiska rymdorganisationen (ESA)
A. Correia
Universidade de Coimbra
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
Eötvös Loránd University (ELTE)
Universität Bern
A. Derekas
Eötvös Loránd University (ELTE)
Billy Edwards
Netherlands Institute for Space Research (SRON)
J. A. Egger
Eötvös Loránd University (ELTE)
Anders Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
A. Fortier
Eötvös Loránd University (ELTE)
Universität Bern
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Universiteit Leiden
D. Gandolfi
Universita degli Studi di Torino
K. Gazeas
University of Athens
Michaël Gillon
Universite de Liège
M. Gudel
Universität Wien
P. Guterman
Division Technique INSU
Laboratoire d'Astrophysique de Marseille
J. Hasiba
Institut fur Weltraumforschung
Ch. Helling
Technische Universität Graz
Institut fur Weltraumforschung
K. Isaak
Europeiska rymdorganisationen (ESA)
L. L. Kiss
Research Centre For Astronomy and Earth Sciences
Magyar Tudomanyos Akademia
Eötvös Loránd University (ELTE)
Judith Korth
Université de Genève
K. W.F. Lam
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Laskar
Observatoire de Paris
A. Lecavelier des Etangs
Centre national de la recherche scientifique (CNRS)
A. Leleu
Eötvös Loránd University (ELTE)
Université de Genève
M. Lendl
Université de Genève
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
Bruno Merín
Europeiska rymdorganisationen (ESA)
C. Mordasini
Eötvös Loránd University (ELTE)
M. Munari
Istituto nazionale di astrofisica (INAF)
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
G. Olofsson
Stockholms universitet
R. Ottensamer
Universität Wien
I. Pagano
Istituto nazionale di astrofisica (INAF)
Enric Palle
Universidad de la Laguna
Instituto de Astrofísica de Canarias
G. Peter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
D. Piazza
Universität Bern
Giampaolo P. Piotto
Istituto nazionale di astrofisica (INAF)
Università di Padova
Don L. Pollacco
The University of Warwick
D. Queloz
Eidgenössische Technische Hochschule Zürich (ETH)
University of Cambridge
Roberto Ragazzoni
Istituto nazionale di astrofisica (INAF)
Università di Padova
N. Rando
Europeiska rymdorganisationen (ESA)
H. Rauer
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Freie Universität Berlin
I. Ribas
Consejo Superior de Investigaciones Científicas (CSIC)
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
N. C. Santos
Universidade do Porto
D. Segransan
Université de Genève
M. Stalport
Universite de Liège
S. Sulis
Laboratoire d'Astrophysique de Marseille
S. Udry
Université de Genève
B. Ulmer
Universität Bern
S. Ulmer-Moll
Eötvös Loránd University (ELTE)
Universite de Liège
Université de Genève
V. Van Grootel
Universite de Liège
J. Venturini
Université de Genève
E. Villaver
Instituto de Astrofísica de Canarias
Universidad de la Laguna
N. A. Walton
University of Cambridge
S. Wolf
Universität Bern
Tiziano Zingales
Università di Padova
Istituto nazionale di astrofisica (INAF)
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 701 A240Ämneskategorier (SSIF 2025)
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/202554040