We apply the previously suggested accretion model for the behavior of the super-massive binary system η Car close to periastron passages. In that model it is assumed that for ∼ 10 weeks near periastron passages one star is accreting mass from the slow dense wind blown by the other star. We find that the secondary, the less massive star, accretes ∼ 2 × 10- 6 Mȯ. This mass possesses enough angular momentum to form a disk, or a belt, around the secondary. The viscous time is too long for the establishment of equilibrium, and the belt must be dissipated as its mass is being blown in the reestablished secondary wind. This process requires about half a year, which we identify with the recovery phase of η Car. We show that radiation pressure, termed radiative braking, cannot prevent accretion. In addition to using the commonly assumed binary model for η Car, we also examine alternative models where the stellar masses are larger, and/or the less massive secondary blows the slow dense wind, while the primary blows the tenuous fast wind and accretes mass for ∼ 10 week near periastron passages. We end by some predictions for the next event (January-March 2009).
Bibliographical noteFunding Information:
We thank the referee for useful comments. This research was supported in part by the Asher Fund for Space Research at the Technion.
- (Stars:) binaries: general
- Accretion disks
- Stars: individual (η Car)
- Stars: mass loss
- Stars: winds, outflows