Abstract
KOI-3890 is a highly eccentric, 153-day period eclipsing, single-lined spectroscopic binary system containing a red-giant star showing solar-like oscillations alongside tidal interactions. The combination of transit photometry, radial velocity observations, and asteroseismology have enabled the detailed characterisation of both the red-giant primary and the M-dwarf companion, along with the tidal interaction and the geometry of the system. The stellar parameters of the red-giant primary are determined through the use of asteroseismology and grid-based modelling to give a mass and radius of M*=1.04±0.06M⊙ and R*=5.8±0.2R⊙ respectively. When combined with transit photometry the M-dwarf companion is found to have a mass and radius of MC=0.23±0.01M⊙ and RC=0.256±0.007R⊙. Moreover, through asteroseismology we constrain the age of the system through the red-giant primary to be 9.1+2.4-1.7 Gyr. This provides a constraint on the age of the M-dwarf secondary, which is difficult to do for other M-dwarf binary systems. In addition, the asteroseismic analysis yields an estimate of the inclination angle of the rotation axis of the red-giant star of i=87.6+2.4-1.2 degrees. The obliquity of the system - the angle between the stellar rotation axis and the angle normal to the orbital plane - is also derived to give ψ=4.2+2.1-4.2 degrees showing that the system is consistent with alignment. We observe no radius inflation in the M-dwarf companion when compared to current low-mass stellar models.
Original language | English |
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Pages (from-to) | 14–23 |
Number of pages | 8 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 487 |
Issue number | 1 |
Early online date | 2 May 2019 |
DOIs | |
Publication status | Published - 1 Jul 2019 |
Bibliographical note
11 pages, 5 figures, accepted for publication in MNRASKeywords
- asteroseismology
- astro-ph.SR
- binaries: eclipsing
- stars: evolution
- stars: fundamental parameters
- techniques: photometric