MESA models of the evolutionary state of the interacting binary epsilon Aurigae

作者：Gibson Justus L^*; Stencel Robert E^*

来源：Monthly Notices of the Royal Astronomical Society, 2018, 476(4): 5026-5031.

DOI：10.1093/mnras/sty639

• nuclear reactions, nucleosynthesis, abundances
• binaries: eclipsing
• stars: evolution
• stars: individual: epsilon Aurigae

Using MESA code (Modules for Experiments in Stellar Astrophysics, version 9575), an evaluation was made of the evolutionary state of the epsilon Aurigae binary system (HD 31964, F0Iap + disc). We sought to satisfy several observational constraints: (1) requiring evolutionary tracks to pass close to the current temperature and luminosity of the primary star; (2) obtaining a period near the observed value of 27.1 years; (3) matching a mass function of 3.0; (4) concurrent Roche lobe overflow and mass transfer; (5) an isotopic ratio 12C/13C = 5 and, (6) matching the interferometrically determined angular diameter. A MESA model starting with binary masses of 9.85 + 4.5 M circle dot, with a 100 d initial period, produces a 1.2 + 10.6 M circle dot result having a 547 d period, and a single digit 12C/13C ratio. These values were reached near an age of 20 Myr, when the donor star comes close to the observed luminosity and temperature for epsilon Aurigae A, as a post-RGB/pre-AGB star. Contemporaneously, the accretor then appears as an upper main-sequence, early B-type star. This benchmark model can provide a basis for further exploration of this interacting binary, and other long-period binary stars.

• 出版日期2018-6