The K2-24 planetary system revisited by CHEOPS
(2024) In Astronomy and Astrophysics 690.- Abstract
- 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... (More)
- 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. © The Authors 2024. (Less)
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https://lup.lub.lu.se/record/a23af5ac-4a96-498c-aa49-3eeda2f17f38
- author
- Nascimbeni, V. ; Davies, M.B. LU ; Korth, J. LU and Walton, N.A.
- author collaboration
- organization
- publishing date
- 2024
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Planets and satellites: detection, Planets and satellites: dynamical evolution and stability, Planets and satellites: gaseous planets, Techniques: photometric, Techniques: spectroscopic, Cosmology, Orbits, Solar system, Planet and satellite: gaseous planet, Planetary system, Planets and satellites, Planets and satellites: detections, Planets and satellites: dynamical evolution and stabilities, Time variations, Transit-time, Zero eccentricity, Planets
- in
- Astronomy and Astrophysics
- volume
- 690
- article number
- A349
- publisher
- EDP Sciences
- external identifiers
-
- scopus:85207399984
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361/202450852
- language
- English
- LU publication?
- yes
- id
- a23af5ac-4a96-498c-aa49-3eeda2f17f38
- date added to LUP
- 2025-08-29 14:40:15
- date last changed
- 2025-08-29 14:40:49
@article{a23af5ac-4a96-498c-aa49-3eeda2f17f38,
abstract = {{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. © The Authors 2024.}},
author = {{Nascimbeni, V. and Davies, M.B. and Korth, J. and Walton, N.A.}},
issn = {{0004-6361}},
keywords = {{Planets and satellites: detection; Planets and satellites: dynamical evolution and stability; Planets and satellites: gaseous planets; Techniques: photometric; Techniques: spectroscopic; Cosmology; Orbits; Solar system; Planet and satellite: gaseous planet; Planetary system; Planets and satellites; Planets and satellites: detections; Planets and satellites: dynamical evolution and stabilities; Time variations; Transit-time; Zero eccentricity; Planets}},
language = {{eng}},
publisher = {{EDP Sciences}},
series = {{Astronomy and Astrophysics}},
title = {{The K2-24 planetary system revisited by CHEOPS}},
url = {{http://dx.doi.org/10.1051/0004-6361/202450852}},
doi = {{10.1051/0004-6361/202450852}},
volume = {{690}},
year = {{2024}},
}