The multi-planet system TOI-5624: four transiting sub-Neptunes with an outer companion revealed by transit-timing variations
Artikel i vetenskaplig tidskrift, 2026
Context. Following the 2022 alert of a TESS object of interest transiting TOI-5624 (a G7 V star similar to 100 pc away), a CHEOPS campaign in 2023 detected four planetary signals at P-b approximate to 3.4, P-c approximate to 7.9, P-d approximate to 13.7, and P-e approximate to 21.5 days. These signals were later confirmed by additional TESS and CHEOPS photometry in 2024-2025. Aims. By using TESS and CHEOPS photometry, along with HARPS-N and SOPHIE high-resolution spectra, we determined the planet properties and performed a dynamical analysis of the system. Methods. After analysing the photometric data, we extracted and modelled the radial velocity (RV) time series using two independent methodologies, both within a Markov chain Monte Carlo framework. We further integrated the N-body equations of motion, while simultaneously fitting the transit times and the detrended RVs, to dynamically characterise the system. Results. We present the discovery of four transiting sub-Neptunes with radii of R-b = 2.314 +/- 0.035 R-circle plus, R-c = 2.474 +/- 0.042 R-circle plus, R-d = 3.584(-0.050)(+0.051)R(circle plus), and R-e = 3.247(-0.043)(+0.042)R(circle plus), along with masses of M-b = 9.4 +/- 1.4M(circle plus), M-c = 4.8 +/- 1.9M(circle plus), Md = 4.9 +/- 2.2M(circle plus), and M-e = 8.9(-3.0)(+2.9)M(circle plus). Our photometric analysis revealed that the outermost transiting planet TOI-5624e shows significant transit-timing variations (TTVs). Indeed, we found a robust Keplerian signal in the RV time series close to the 2:1 period commensurability with TOI-5624 e, which explains the TTV pattern exhibited by TOI-5624 e according to our dynamical analysis. We labelled this non-transiting planet as TOI-5624 f and determined its minimum mass to be M-f sin i(f) = 13.0 +/- 3.7 M-circle plus. Conclusions. Among the known systems hosting more than four planets, the remarkable precision with which the radii have been measured (<1.7%) and the firm assessment (>3 sigma) of the mass for at least three planets has previously been reached only for TRAPPIST-1. Additional photometric observations will enable a better sample of the TTV modulation and a more robust dynamical determination of the masses.
techniques: radial velocities
planets and satellites: fundamental parameters
techniques: photometric
stars: fundamental parameters
Författare
A. Bonfanti
Österreichische Akademie der Wissenschaften
D. Gandolfi
Universita degli Studi di Torino
P. Leonardi
Universita degli Studi di Trento
Università di Padova
H. P. Osborn
Universität Bern
Eidgenössische Technische Hochschule Zürich (ETH)
L. M. Serrano
Universita degli Studi di Torino
G. Hebrard
Aix-Marseille Université
Université Pierre et Marie Curie (UPMC)
N. Billot
Université de Genève
A. Bekkelien
Université de Genève
G. Olofsson
Stockholms universitet
C. Broeg
Universität Bern
D. Nardiello
Università di Padova
Istituto nazionale di astrofisica (INAF)
S. G. Sousa
Universidade do Porto
T. G. Wilson
The University of Warwick
A. C. M. Correia
Universidade de Coimbra
C. Pezzotti
Universite de Liège
A. Brandeker
Stockholms universitet
L. Fossati
Österreichische Akademie der Wissenschaften
M. Gillon
Universite de Liège
M. Stalport
Universite de Liège
B. Akinsanmi
Université de Genève
Y. Alibert
Universität Bern
R. Alonso
Universidad de la Laguna
Instituto de Astrofísica de Canarias
J. Asquier
Europeiska rymdorganisationen (ESA)
T. Barczy
Admatis
D. Barrado
Consejo Superior de Investigaciones Científicas (CSIC)
S. C. C. Barros
Universidade do Porto
W. Baumjohann
Österreichische Akademie der Wissenschaften
W. Benz
Universität Bern
L. Borsato
Istituto nazionale di astrofisica (INAF)
A. Castro-Gonzalez
Université de Genève
A. Collier Cameron
University of St Andrews
Sz. Csizmadia
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
P. E. Cubillos
Istituto nazionale di astrofisica (INAF)
Österreichische Akademie der Wissenschaften
M. B. Davies
Lunds universitet
M. Deleuil
Aix-Marseille Université
X. Delfosse
Université Grenoble Alpes
A. Deline
Université de Genève
O. D. S. Demangeon
Universidade do Porto
B. O. Demory
Universität Bern
A. Derekas
Eötvös Loránd University (ELTE)
F. Destriez
Université Pierre et Marie Curie (UPMC)
Université Paris Descartes
B. Edwards
Netherlands Institute for Space Research (SRON)
D. Ehrenreich
Université de Genève
A. Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
A. Fortier
Universität Bern
Malcolm Fridlund
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
K. Gazeas
National and Kapodistrian University of Athens
M. Gudel
Universität Wien
M. N. Gunther
Europeiska rymdorganisationen (ESA)
N. Hara
Aix-Marseille Université
N. Heidari
Université Pierre et Marie Curie (UPMC)
A. Heitzmann
Université de Genève
Ch. Helling
Technische Universität Graz
Österreichische Akademie der Wissenschaften
K. G. Isaak
Europeiska rymdorganisationen (ESA)
T. Keller
Universität Bern
L. L. Kiss
Eötvös Loránd University (ELTE)
Magyar Tudomanyos Akademia
D. Kitzmann
Universität Bern
J. Korth
Université de Genève
G. Lacedelli
Instituto de Astrofísica de Canarias
K. W. F. Lam
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Laskar
Sorbonne Université
A. Lecavelier des Etangs
Université Pierre et Marie Curie (UPMC)
A. Leleu
Université de Genève
Universität Bern
M. Lendl
Université de Genève
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. F. L. Maxted
Keele University
M. Mecina
Universität Wien
B. Merin
Europeiska rymdorganisationen (ESA)
C. Mordasini
Universität Bern
V. Nascimbeni
Istituto nazionale di astrofisica (INAF)
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)
D. Piazza
Universität Bern
G. Piotto
Istituto nazionale di astrofisica (INAF)
Università di Padova
D. Pollacco
The University of Warwick
D. Queloz
University of Cambridge
Eidgenössische Technische Hochschule Zürich (ETH)
R. Ragazzoni
Università di Padova
Istituto nazionale di astrofisica (INAF)
N. Rando
Europeiska rymdorganisationen (ESA)
H. Rauer
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Freie Universität Berlin
I. Ribas
Inst Estudis Espacials Catalunya IEEC
Consejo Superior de Investigaciones Científicas (CSIC)
N. C. Santos
Universidade do Porto
G. 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)
S. Sulis
Aix-Marseille Université
Gy. M. Szabo
Eötvös Loránd University (ELTE)
S. Udry
Université de Genève
S. Ulmer-Moll
Universiteit Leiden
Universite de Liège
V. Van Grootel
Universite de Liège
J. Venturini
Université de Genève
F. Verrecchia
Agenzia Spaziale Italiana
Istituto nazionale di astrofisica (INAF)
E. Villaver
Instituto de Astrofísica de Canarias
Universidad de la Laguna
N. A. Walton
University of Cambridge
S. Wolf
Universität Bern
D. Wolter
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
T. Zingales
Istituto nazionale di astrofisica (INAF)
Università di Padova
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 709 A265Satellitstudier av exoplaneters mångfald
Rymdstyrelsen (174/18), 2019-02-04 -- 2023-08-01.
Exoplaneter från rymden - CHEOPS och PLATO, ESA's nästa två rymdteleskop (fas 2)
Rymdstyrelsen (177/19), 2020-01-01 -- 2022-12-31.
Rymdstyrelsen (65/19), 2020-01-01 -- 2022-12-31.
Ämneskategorier (SSIF 2025)
Astronomi, astrofysik och kosmologi
Subatomär fysik
DOI
10.1051/0004-6361/202558740