密近双星的质量比分布  

Mass Ratio Distribution of Close Binary

作　　者：王禄齐 刘超 WANG Luqi;LIU Chao(University of Chinese Academy of Sciences,Beijing 100049,China;National Astronomical Observatories,Chinese Academy of Science,Beijing 100101,China)

机构地区：[1]中国科学院大学,北京100049 [2]中国科学院国家天文台,北京100101

出　　处：《天文学进展》2024年第4期628-638,共11页Progress In Astronomy

摘　　要：双星演化是恒星物理的一个重要课题,它不仅对恒星研究,也对星系演化、超新星和宇宙学等研究有重要影响。LAMOST时域巡天提供了大量的双星样本,这对研究密近双星的统计性质非常重要。该文选择一批具有LAMOST时域光谱观测的主序短周期双星(主星质量在0.7M_(⊙)~2.2M_(⊙)之间)作为研究对象,通过the Joker获得了部分样本的双星轨道参数,并经由质量选择效应改正获得了这些密近双星的质量比分布。假设质量比分布的形式为在质量比为0.4处分段的双幂律再加大质量比双星超出组成,其中大质量比双星成分假设为在0.8~1之间的以1为中心的高斯分布形式。分别以有bin和无bin两种方式得到了质量比分布的最佳拟合,发现无bin的拟合效果更好。结果显示,对质量比小于0.4的部分,幂指数为-1.23±0.04;而质量比在0.4~0.8之间时幂指数为-4.52±0.07。这一结果表明,密近双星质量比分布与宽距双星的质量比分布在统计上并不相同,也不能用初始质量函数随机配对进行解释。这可能是因为密近双星经历了更复杂的动力学演化,从而改变了质量比分布的统计特征。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 is1:23±0.04;When the mass ratio is between 0.4 and 0.8,the power index is4:52±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.

关 键 词：恒星 双星 质量比 

分 类 号：P144.9[天文地球—天体物理]