TOI−757 b: an eccentric transiting mini−Neptune on a 17.5−d orbit
(2024) In Monthly Notices of the Royal Astronomical Society 533(1). p.1-26- Abstract
- We report the spectroscopic confirmation and fundamental properties of TOI−757 b, a mini−Neptune on a 17.5−d orbit transiting a bright star (V = 9.7 mag) discovered by the TESS mission. We acquired high−precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine its mass. We also acquired space−borne transit photometry with the CHEOPS space telescope to place stronger constraints on the planet radius, supported with ground−based LCOGT photometry. WASP and KELT photometry were used to help constrain the stellar rotation period. We also determined the fundamental parameters of the host star. We find that TOI−757 b has a radius of Rp = 2.5 ± 0.1R. and a mass of Mp =... (More)
- We report the spectroscopic confirmation and fundamental properties of TOI−757 b, a mini−Neptune on a 17.5−d orbit transiting a bright star (V = 9.7 mag) discovered by the TESS mission. We acquired high−precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine its mass. We also acquired space−borne transit photometry with the CHEOPS space telescope to place stronger constraints on the planet radius, supported with ground−based LCOGT photometry. WASP and KELT photometry were used to help constrain the stellar rotation period. We also determined the fundamental parameters of the host star. We find that TOI−757 b has a radius of Rp = 2.5 ± 0.1R. and a mass of Mp = 10.5+−2212M, implying a bulk density of ρp = 3.6 ± 0.8 g cm−3. Our internal composition modelling was unable to constrain the composition of TOI−757 b, highlighting the importance of atmospheric observations for the system. We also find the planet to be highly eccentric with e = 0.39+−000708, making it one of the very few highly eccentric planets among precisely characterized mini−Neptunes. Based on comparisons to other similar eccentric systems, we find a likely scenario for TOI−757 b’s formation to be high eccentricity migration due to a distant outer companion. We additionally propose the possibility of a more intrinsic explanation for the high eccentricity due to star−star interactions during the earlier epoch of the Galactic disc formation, given the low metallicity and older age of TOI−757. © 2024 The Author(s). (Less)
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- author
- Alqasim, A. ; Daylan, T. ; Laskar, J. and Yee, S. W.
- author collaboration
- publishing date
- 2024
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- planets and satellites: composition, planets and satellites: interiors, stars: individual: TOI-757 (TIC 130924120), techniques: photometric, techniques: radial velocities, Orbits, Planets, Satellites, Stars, Fundamental properties, High-precision, Neptune, Planets and satellites: compositions, Planets and satellites: interiors, Radial velocity measurements, Star: individual: TOI-757 (TIC 130924120), Stars: individual: proxima Centauri, Techniques: photometric, Techniques: radial velocities, Photometry
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 533
- issue
- 1
- pages
- 26 pages
- publisher
- Oxford University Press
- external identifiers
-
- scopus:85200850226
- ISSN
- 0035-8711
- DOI
- 10.1093/mnras/stae1767
- language
- English
- LU publication?
- no
- id
- d02a8b40-1733-4408-9d75-f5f82d09b6fa
- date added to LUP
- 2024-09-03 14:33:09
- date last changed
- 2024-09-03 14:33:34
@article{d02a8b40-1733-4408-9d75-f5f82d09b6fa,
abstract = {{We report the spectroscopic confirmation and fundamental properties of TOI−757 b, a mini−Neptune on a 17.5−d orbit transiting a bright star (V = 9.7 mag) discovered by the TESS mission. We acquired high−precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine its mass. We also acquired space−borne transit photometry with the CHEOPS space telescope to place stronger constraints on the planet radius, supported with ground−based LCOGT photometry. WASP and KELT photometry were used to help constrain the stellar rotation period. We also determined the fundamental parameters of the host star. We find that TOI−757 b has a radius of Rp = 2.5 ± 0.1R. and a mass of Mp = 10.5+−2212M, implying a bulk density of ρp = 3.6 ± 0.8 g cm−3. Our internal composition modelling was unable to constrain the composition of TOI−757 b, highlighting the importance of atmospheric observations for the system. We also find the planet to be highly eccentric with e = 0.39+−000708, making it one of the very few highly eccentric planets among precisely characterized mini−Neptunes. Based on comparisons to other similar eccentric systems, we find a likely scenario for TOI−757 b’s formation to be high eccentricity migration due to a distant outer companion. We additionally propose the possibility of a more intrinsic explanation for the high eccentricity due to star−star interactions during the earlier epoch of the Galactic disc formation, given the low metallicity and older age of TOI−757. © 2024 The Author(s).}},
author = {{Alqasim, A. and Daylan, T. and Laskar, J. and Yee, S. W.}},
issn = {{0035-8711}},
keywords = {{planets and satellites: composition; planets and satellites: interiors; stars: individual: TOI-757 (TIC 130924120); techniques: photometric; techniques: radial velocities; Orbits; Planets; Satellites; Stars; Fundamental properties; High-precision; Neptune; Planets and satellites: compositions; Planets and satellites: interiors; Radial velocity measurements; Star: individual: TOI-757 (TIC 130924120); Stars: individual: proxima Centauri; Techniques: photometric; Techniques: radial velocities; Photometry}},
language = {{eng}},
number = {{1}},
pages = {{1--26}},
publisher = {{Oxford University Press}},
series = {{Monthly Notices of the Royal Astronomical Society}},
title = {{TOI−757 b: an eccentric transiting mini−Neptune on a 17.5−d orbit}},
url = {{http://dx.doi.org/10.1093/mnras/stae1767}},
doi = {{10.1093/mnras/stae1767}},
volume = {{533}},
year = {{2024}},
}