HD 89345 : A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2
(2018) In Monthly Notices of the Royal Astronomical Society 478(4). p.4866-4880- Abstract
We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding themass and radius to be 1.12-0.01+0.04 M⊙ and 1.657 -0.004 +0.020 R⊙, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4-1.3+0.4 Gyr, and the non-detection of mixed modes. The star hosts a 'warm Saturn' (P = 11.8 d, Rp = 6.86 ± 0.14... (More)
We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding themass and radius to be 1.12-0.01+0.04 M⊙ and 1.657 -0.004 +0.020 R⊙, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4-1.3+0.4 Gyr, and the non-detection of mixed modes. The star hosts a 'warm Saturn' (P = 11.8 d, Rp = 6.86 ± 0.14 R⊕). Radial-velocity follow-up observations performed with the FIbre-fed Echelle Spectrograph, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M⊕. The data also show that the planet's orbit is eccentric (e≈0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to confirm to the same patterns that have been observed for other sub-Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity.
(Less)
- author
- publishing date
- 2018-08-21
- type
- Contribution to journal
- publication status
- published
- keywords
- Asteroseismology, Planets and satellites: composition, Planets and satellites: formation, Planets and satellites: fundamental parameters
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 478
- issue
- 4
- pages
- 15 pages
- publisher
- Oxford University Press
- external identifiers
-
- scopus:85050797619
- ISSN
- 0035-8711
- DOI
- 10.1093/mnras/sty1390
- language
- English
- LU publication?
- no
- additional info
- Publisher Copyright: © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
- id
- f7765d7d-2d98-43f3-9505-b7aa26ce961b
- date added to LUP
- 2023-02-02 11:25:04
- date last changed
- 2023-02-27 13:01:48
@article{f7765d7d-2d98-43f3-9505-b7aa26ce961b,
abstract = {{<p>We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding themass and radius to be 1.12-<sub>0.01</sub><sup>+0.04</sup> M<sub>⊙</sub> and 1.657 <sub>-0.004</sub> <sup>+0.020</sup> R<sub>⊙</sub>, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4<sub>-1.3</sub><sup>+0.4</sup> Gyr, and the non-detection of mixed modes. The star hosts a 'warm Saturn' (P = 11.8 d, R<sub>p</sub> = 6.86 ± 0.14 R<sub>⊕</sub>). Radial-velocity follow-up observations performed with the FIbre-fed Echelle Spectrograph, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M<sub>⊕</sub>. The data also show that the planet's orbit is eccentric (e≈0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to confirm to the same patterns that have been observed for other sub-Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity.</p>}},
author = {{Van Eylen, V. and Dai, F. and Mathur, S. and Gandolfi, D. and Albrecht, S. and Fridlund, M. and García, R. A. and Guenther, E. and Hjorth, M. and Justesen, A. B. and Livingston, J. and Lund, M. N. and Pérez Hernández, F. and Prieto-Arranz, J. and Regulo, C. and Bugnet, L. and Everett, M. E. and Hirano, T. and Nespral, D. and Nowak, G. and Palle, E. and Silva Aguirre, V. and Trifonov, T. and Winn, J. N. and Barragán, O. and Beck, P. G. and Chaplin, W. J. and Cochran, W. D. and Csizmadia, S. and Deeg, H. and Endl, M. and Heeren, P. and Grziwa, S. and Hatzes, A. P. and Hidalgo, D. and Korth, J. and Mathis, S. and Rodriguez, P. Montañes and Narita, N. and Patzold, M. and Persson, C. M. and Rodler, F. and Smith, A. M.S.}},
issn = {{0035-8711}},
keywords = {{Asteroseismology; Planets and satellites: composition; Planets and satellites: formation; Planets and satellites: fundamental parameters}},
language = {{eng}},
month = {{08}},
number = {{4}},
pages = {{4866--4880}},
publisher = {{Oxford University Press}},
series = {{Monthly Notices of the Royal Astronomical Society}},
title = {{HD 89345 : A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2}},
url = {{http://dx.doi.org/10.1093/mnras/sty1390}},
doi = {{10.1093/mnras/sty1390}},
volume = {{478}},
year = {{2018}},
}