Asteroseismology of KIC 7107778: a binary comprising almost identical subgiants
Article
Article Title | Asteroseismology of KIC 7107778: a binary comprising almost identical subgiants |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Li, Yaguang (Author), Bedding, Timothy R. (Author), Li, Tanda (Author), Bi, Shaolan (Author), Murphy, Simon J. (Author), Corsaro, Enrico (Author), Chen, Li (Author) and Tian, Zhijia (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 476 (1), pp. 470-481 |
Number of Pages | 12 |
Year | 2018 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/sty222 |
Web Address (URL) | https://academic.oup.com/mnras/article/476/1/470/4828389 |
Abstract | We analyse an asteroseismic binary system: KIC 7107778, a non-eclipsing, unresolved target, with solar-like oscillations in both components. We used Kepler short cadence time series spanning nearly 2 yr to obtain the power spectrum. Oscillation mode parameters were determined using Bayesian inference and a nested sampling Monte Carlo algorithm with the DIAMONDS package. The power profiles of the two components fully overlap, indicating their close similarity. We modelled the two stars with MESA and calculated oscillation frequencies with GYRE. Stellar fundamental parameters (mass, radius, and age) were estimated by grid modelling with atmospheric parameters and the oscillation frequencies of l = 0, 2 modes as constraints. Most l = 1 mixed modes were identified with models searched using a bisection method. Stellar parameters for the two sub-giant stars are MA = 1.42 ± 0.06 M⊙, MB = 1.39 ± 0.03 M⊙, RA = 2.93 ± 0.05 R⊙, RB = 2.76 ± 0.04 R⊙, tA = 3.32 ± 0.54 Gyr and tB = 3.51 ± 0.33 Gyr. The mass difference of the system is ∼1 per cent. The results confirm their simultaneous birth and evolution, as is expected from binary formation. KIC 7107778 comprises almost identical twins, and is the first asteroseismic sub-giant binary to be detected. |
Keywords | Binaries: general; Stars: evolution; Stars: oscillations; Astrophysics - Solar and Stellar Astrophysics |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | Beijing Normal University, China |
University of Sydney | |
National Institute for Astrophysics, Italy | |
Peking University, China | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q7397/asteroseismology-of-kic-7107778-a-binary-comprising-almost-identical-subgiants
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