Journal article
Transit timings variations in the three-planet system: TOI-270
- Abstract:
- We present ground- and space-based photometric observations of TOI-270 (L231-32), a system of three transiting planets consisting of one super-Earth and two sub-Neptunes discovered by TESS around a bright (K-mag = 8.25) M3V dwarf. The planets orbit near low-order mean-motion resonances (5:3 and 2:1) and are thus expected to exhibit large transit timing variations (TTVs). Following an extensive observing campaign using eight different observatories between 2018 and 2020, we now report a clear detection of TTVs for planets c and d, with amplitudes of ∼10 min and a super-period of ∼3 yr, as well as significantly refined estimates of the radii and mean orbital periods of all three planets. Dynamical modelling of the TTVs alone puts strong constraints on the mass ratio of planets c and d and on their eccentricities. When incorporating recently published constraints from radial velocity observations, we obtain masses of Mb=1.48± 0.18, M⊕, Mc=6.20± 0.31, M⊕, and Md=4.20± 0.16, M⊕ for planets b, c, and d, respectively. We also detect small but significant eccentricities for all three planets: eb = 0.0167 ± 0.0084, ec = 0.0044 ± 0.0006, and ed = 0.0066 ± 0.0020. Our findings imply an Earth-like rocky composition for the inner planet, and Earth-like cores with an additional He/H2O atmosphere for the outer two. TOI-270 is now one of the best constrained systems of small transiting planets, and it remains an excellent target for atmospheric characterization.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, pdf, 4.2MB, Terms of use)
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- Publisher copy:
- 10.1093/mnras/stab3483
Authors
- Publisher:
- Oxford University Press
- Journal:
- Monthly Notices of the Royal Astronomical Society More from this journal
- Volume:
- 510
- Issue:
- 4
- Pages:
- 5464-5485
- Publication date:
- 2021-12-06
- Acceptance date:
- 2021-11-23
- DOI:
- EISSN:
-
1365-2966
- ISSN:
-
0035-8711
- Language:
-
English
- Keywords:
- Pubs id:
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1243511
- Local pid:
-
pubs:1243511
- Deposit date:
-
2023-08-15
Terms of use
- Copyright holder:
- Kaye et al
- Copyright date:
- 2022
- Rights statement:
- © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
- Notes:
- This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©2021, Kaye et al. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
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