1. On the period–density relations and lower period limit of contact binaries.
- Author
-
Zhang, Xiaobin, Chen, Xinghao, Fu, Jianning, and Li, Yan
- Subjects
- *
DENSITY of stars , *STELLAR mass , *LOW mass stars , *ROOT-mean-squares , *BINARY stars - Abstract
The theoretical relations between the orbital period and mean densities of component stars of contact binaries are deduced. It is found that the orbital period of a contact binary is inversely proportional to the square root of the mean densities of component stars with the slopes as functions of mass ratio and fill-out factor of system. A test of 148 well-studied contact binaries with physical parameters determined from comprehensive photometric and spectroscopic solutions shows that the upper limit of secondaries' mean densities depends strongly on the total masses, M 1 + M 2, of the contact systems. For a low-mass contact system with |$(M_{}+M_{2})\le 2\, \mathrm{M}_{\odot }$| , the maximum mean density of the secondary is strictly lower than that of a 5 Gyr star with a mass of (M + M 2)/2. Taking this as the basic constraint, the derived period–density relation was applied to simulate the orbital period distribution of low-mass contact binaries over the total-mass range of 1–2 |$\, \mathrm{M}_{\odot }$|. It reproduces a period cut-off at 0.12–0.16 d, depending on the fill-out factor. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF