English

Two twin binaries with nearly identical components: KIC 4826439 and KIC 6045264

Solar and Stellar Astrophysics 2017-10-17 v1

Abstract

Two twin binaries, KIC 4826439 and KIC 6045264, with very similar component stars were found photometrically based on Kepler\textit{Kepler} eclipsing binary light curves. The absolute parameters of the massive components are 1.156(0.03)MM_\odot, 1.881(0.02)RR_\odot, 6065K for KIC 4826439, and 0.874(0.3)MM_\odot, 1.206(0.02)RR_\odot, 6169(30)K for KIC 6045264. The differences between the components are less than two percents for all the parameters. A very low proportion of the twin binaries (2/15920.13%2/1592\approx0.13\%) was found, which does not support the previous findings of the excesses of twins on binary mass ratio distribution, but support a deficiently low proportion of twins. A new method is practiced to work out the absolute parameters of the two twins without the radial velocities. This method requires the solution of the light curves, the spectra and the evolutionary isochrones of covering the complete stellar parameter space, simultaneously. We also studied their evolution tracks that: KIC 4826439 will experience an unstable mass transfer stage followed by an unclear ending, and KIC 6045264 will become a single star via an over-contact phase. It seems highly unlikely that the two twin binaries will produce twin degenerate binaries, although they have quite similar components.

Keywords

Cite

@article{arxiv.1710.04794,
  title  = {Two twin binaries with nearly identical components: KIC 4826439 and KIC 6045264},
  author = {Jia Zhang and Sheng-Bang Qian and Shu-Min Wang and Yue Wu and Lin-Qiao Jiang},
  journal= {arXiv preprint arXiv:1710.04794},
  year   = {2017}
}

Comments

19 pages, 4 figures