The K2-24 planetary system revisited by CHEOPS
Journal article, 2024
The planetary system K2-24 is composed of two transiting low-density Neptunians locked in an almost perfect 2:1 resonance and showing large transit time variations (TTVs), and it is an excellent laboratory to search for signatures of planetary migration. Previous studies performed with K2, Spitzer, and RV data tentatively claimed a significant non-zero eccentricity for one or both planets, possibly high enough to challenge the scenario of pure disk migration through resonant capture. With 13 new CHEOPS light curves (seven of planet b, six of planet c), we carried out a global photometric and dynamical re-analysis by including all the available literature data as well. We obtained the most accurate set of planetary parameters to date for the K2-24 system, including radii and masses at 1% and 5% precision (now essentially limited by the uncertainty on stellar parameters) and non-zero eccentricities eb = 0.0498-0.0018+0.0011, ec = 0.0282-0.0007+0.0003 detected at very high significance for both planets. Such relatively large values imply the need for an additional physical mechanism of eccentricity excitation during or after the migration stage. Also, while the accuracy of the previous TTV model had drifted by up to 0.5 days at the current time, we constrained the orbital solution firmly enough to predict the forthcoming transits for the next ~15 years, thus enabling efficient follow-up with top-level facilities such as JWST or ESPRESSO.
Techniques: photometric
Planets and satellites: dynamical evolution and stability
Planets and satellites: gaseous planets
Techniques: spectroscopic
Planets and satellites: detection
Author
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
L. Borsato
Istituto nazionale di astrofisica (INAF)
P. Leonardi
University of Padua
University of Trento
Istituto nazionale di astrofisica (INAF)
S.G. Sousa
University of Porto
T.G. Wilson
The University of Warwick
A. Fortier
University of Bern
A. Heitzmann
University of Geneva
G. Mantovan
University of Padua
Istituto nazionale di astrofisica (INAF)
R. Luque
University of Chicago
Tiziano Zingales
Istituto nazionale di astrofisica (INAF)
University of Padua
Giampaolo P. Piotto
Istituto nazionale di astrofisica (INAF)
University of Padua
Y. Alibert
University of Bern
R. Alonso
University of La Laguna
Instituto de Astrofísica de Canarias
T. Bárczy
Admatis
D. Barrado Navascues
European Space Astronomy Centre (ESAC)
S.C.C. Barros
University of Porto
W. Baumjohann
Institut fur Weltraumforschung
T. Beck
University of Bern
W. Benz
University of Bern
N. Billot
University of Geneva
F. Biondi
Max Planck Society
Istituto nazionale di astrofisica (INAF)
A. Brandeker
Stockholm University
C. Broeg
University of Bern
M.-D. Busch
University of Bern
A. Collier Cameron
University of St Andrews
A. Correia
Centre for Physics of the University of Coimbra
Szilard Csizmadia
German Aerospace Center (DLR)
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)
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)
Ch. Helling
Technische Universität Graz
Institut fur Weltraumforschung
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)
Judith Korth
Lund University
K. W.F. Lam
German Aerospace Center (DLR)
J. Laskar
Paris Observatory
A. L. des Etangs
Institut d 'Astrophysique de Paris
A. Leleu
University of Bern
University of Geneva
M. Lendl
University of Geneva
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
Bruno Merín
European Space Astronomy Centre (ESAC)
C. Mordasini
University of Bern
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)
Don L. 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
Freie Universität Berlin
German Aerospace Center (DLR)
I. Ribas
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
N. C. Santos
University of Porto
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)
R. Southworth
European Space Operations Centre
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
University of La Laguna
Instituto de Astrofísica de Canarias
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 690 A349Subject Categories
Astronomy, Astrophysics and Cosmology
Other Physics Topics
DOI
10.1051/0004-6361/202450852