KOI-3890: A high mass-ratio asteroseismic red-giant$+$M-dwarf eclipsing binary undergoing heartbeat tidal interactions

Research output: Contribution to journalArticle


  • James S. Kuszlewicz
  • Thomas S. H. North
  • Allyson Bieryla
  • David W. Latham
  • Keaton J. Bell
  • Sebastien Deheuvels
  • Mikkel Lund

Colleges, School and Institutes


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.

Bibliographic note

11 pages, 5 figures, accepted for publication in MNRAS


Original languageEnglish
Pages (from-to)14–23
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Early online date2 May 2019
Publication statusPublished - 1 Jul 2019


  • astro-ph.SR, asteroseismology, techniques: photometric, binaries: eclipsing, stars: evolution, stars: fundamental parameters