密近双星的质量比分布OA北大核心CSTPCD

The evolution of binary is an important problem in stellar physics,which has an important impact not only on the study of stars but also on the study of galaxy evolution,supernovae and cosmology.However,observational studies of the statistical properties of binary are still very limited.The LAMOST Time Domain Survey provides a large sample of binary,which is important for studying the statistical properties of close binary.In this paper,a group of main-sequence short-period binary(primary masses are between 0.7M and 2.2M⊙)with LAMOST time-domain spectroscopic observations are selected as research objects.The binary orbit parameters of some samples were obtained by the Joker,and the mass ratio distribution of these close binaries was obtained after the selection effect correction.Here it is assumed that the mass ratio distribution is a segmented power law broken at the mass ratio 0.4 and the high mass ratio binary excess,where the component of the high mass ratio binary is assumed to be between 0.8 and 1 for a Gaussian distribution centered at 1.We get the best fit of the mass ratio distribution with and without bin respectively,and find that the fit without bin is better.The results show that the power index of the parts with mass ratio less than 0.4 is-1.23±0.04;When the mass ratio is between 0.4 and 0.8,the power index is-4.52±0.07.This result shows that the mass ratio distribution of close binary is statistically different from that of wide binary and cannot be explained by random pairing of the initial mass function.This may be because close binaries have undergone more complex dynamic evolution in the past,which has changed the statistical characteristics of the mass ratio distribution.