Hints of a close outer companion to the ultra-hot Jupiter TOI-2109 b
Journal article, 2024
Context. Hot Jupiters (HJs) with close-by planetary companions are rare, with only a handful of them having been discovered so far. This could be due to their suggested dynamical histories, which lead to the possible ejection of other planets. TOI-2109 b is special in this regard because it is the HJ with the closest relative separation from its host star, being separated by less than 2.3 stellar radii. Unexpectedly, transit timing measurements from recently obtained CHEOPS observations show low-amplitude transit-timing variations (TTVs). Aims. We aim to search for signs of orbital decay and to characterise the apparent TTVs in an attempt to gain information about a possible companion. Methods. We fitted the newly obtained CHEOPS light curves using TLCM and extracted the resulting mid-transit timings. Successively, we used these measurements in combination with TESS and archival photometric data and radial velocity (RV) data to estimate the rate of tidal orbital decay of TOI-2109 b, and also to characterise the TTVs using the N-body code TRADES and the photo-dynamical approach of PyTTV. Results. We find tentative evidence at 3σ for orbital decay in the TOI-2109 system when we correct the mid-transit timings using the best-fitting sinusoidal model of the TTVs. We do not detect additional transits in the available photometric data, but find evidence supporting the authenticity of the apparent TTVs, indicating a close-by, outer companion with Pc > 1.125 d. Due to the fast rotation of the star, the new planetary candidate cannot be detected in the available RV measurements, and its parameters can only be loosely constrained by our joint TTV and RV modelling. Conclusions. TOI-2109 could join a small group of rare HJ systems that host close-by planetary companions, only one of which (WASP-47 b) has an outer companion. More high-precision photometric measurements are necessary to confirm the existence of this planetary companion.
methods: data analysis
planets and satellites: dynamical evolution and stability
planet-star interactions
techniques: photometric
planets and satellites: gaseous planets
Author
J. V. Harre
German Aerospace Center (DLR)
A. M.S. Smith
German Aerospace Center (DLR)
S.C.C. Barros
University of Porto
V. Singh
Istituto nazionale di astrofisica (INAF)
Judith Korth
Lund University
A. Brandeker
Stockholm University
A. Collier Cameron
University of St Andrews
M. Lendl
University of Geneva
T.G. Wilson
The University of Warwick
L. Borsato
Istituto nazionale di astrofisica (INAF)
Szilard Csizmadia
German Aerospace Center (DLR)
J. Cabrera
German Aerospace Center (DLR)
H. Parviainen
Instituto de Astrofísica de Canarias
A. Correia
Centre for Physics of the University of Coimbra
B. Akinsanmi
University of Geneva
N. M. Rosário
University of Porto
P. Leonardi
University of Padua
L. M. Serrano
University of Turin
Y. Alibert
University of Bern
R. Alonso
Instituto de Astrofísica de Canarias
University of La Laguna
J. Asquier
European Space Research and Technology Centre (ESA ESTEC)
T. Bárczy
Admatis
D. Barrado Navascues
Centro de Astrobiologia (CAB)
W. Baumjohann
Institut fur Weltraumforschung
W. Benz
University of Bern
N. Billot
University of Geneva
C. Broeg
University of Bern
M.-D. Busch
University of Bern
P. E. Cubillos
Institut fur Weltraumforschung
Istituto nazionale di astrofisica (INAF)
Melvyn B. Davies
Lund University
M. Deleuil
Laboratoire d'Astrophysique de Marseille
A. Deline
University of Geneva
L. Delrez
KU Leuven
University of Liège
O. Demangeon
University of Porto
B.O. Demory
University of Bern
A. Derekas
Eötvös Loránd University (ELTE)
Billy Edwards
Netherlands Institute for Space Research (SRON)
D. Ehrenreich
University of Geneva
Anders Erikson
German Aerospace Center (DLR)
A. Fortier
University of Bern
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Leiden University
D. Gandolfi
University of Turin
K. Gazeas
University of Athens
Michaël Gillon
University of Liège
M. Gudel
University of Vienna
Maximilian N. Günther
European Space Research and Technology Centre (ESA ESTEC)
A. Heitzmann
University of Geneva
Ch. Helling
Institut fur Weltraumforschung
Technische Universität Graz
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L. L. Kiss
Hungarian Academy of Sciences
Eötvös Loránd University (ELTE)
K. W.F. Lam
German Aerospace Center (DLR)
J. Laskar
Paris Observatory
A. Lecavelier des Etangs
Institut d 'Astrophysique de Paris
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
Bruno Merín
European Space Astronomy Centre (ESAC)
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)
Enric Palle
Instituto de Astrofísica de Canarias
University of La Laguna
G. Peter
German Aerospace Center (DLR)
D. Piazza
University of Bern
Giampaolo P. Piotto
University of Padua
Istituto nazionale di astrofisica (INAF)
Don L. Pollacco
The University of Warwick
D. Queloz
Swiss Federal Institute of Technology in Zürich (ETH)
University of Cambridge
Roberto Ragazzoni
University of Padua
Istituto nazionale di astrofisica (INAF)
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
German Aerospace Center (DLR)
Freie Universität Berlin
I. Ribas
Institute of Space Sciences (ICE) - CSIC
Institute of Space Studies of Catalonia (IEEC)
N. C. Santos
University of Porto
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
University of Geneva
A.E. Simon
University of Bern
S.G. Sousa
University of Porto
M. Stalport
University of Liège
S. Sulis
Laboratoire d'Astrophysique de Marseille
G.M. Szabó
Eötvös Loránd University (ELTE)
S. Udry
University of Geneva
B. Ulmer
German Aerospace Center (DLR)
V. Van Grootel
University of Liège
J. Venturini
University of Geneva
E. Villaver
Instituto de Astrofísica de Canarias
University of La Laguna
V. Viotto
Istituto nazionale di astrofisica (INAF)
N. A. Walton
University of Cambridge
Richard G West
The University of Warwick
K. Westerdorff
German Aerospace Center (DLR)
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 692 A254Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/202451068
Related datasets
A close outer companion to TOI-2109 b? : J/A+A/692/A254 [dataset]
URI: https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/692/A254