摘要
本文利用上海天文台40厘米天体照相仪所拍摄的4对底片,在疏散星团M67天区的1067颗恒星中重新确定了星团成员星.在这一工作的基础上进而对星团M67的半径、年龄、距离、赫罗图、光度函数、质量以及速度弥散度和分层效应等作一定深度的讨论.M67的半径为8.6Pc,年龄5.0×10~9年,距离模数(V—M_v)_0=9.63±0.33,相应的距离为843~pc,团的光度质量为1055μ_⊙,位力质量为2750μ_⊙,分析表明M67恒星在空间和速度上都呈现一定程度的质量分层,但这种效应并不明显.
Based on 4 plate pairs with the time baselines of 64—69 years taken with the 40cm astrograph at Zo-Se Station of Shanghai Observatory and by using a new statistical method for membership determination of star clusters, 254 member stars of M67 with proper morion membership probability P≥0.8 are redetermined from 1067 stars in the region of the cluster. From these member stars, the radius, age, distance, HR diagram, luminosity function and the mass of M67 are reasonably determined and the observed proper motion dispersion and mass segregation effects of the member stars are discussed in some details. It is found that the radius of the cluster is ～8.6pc, its age ～5.0×10~9 years, the distance modulus (V—M_v)_0=9.63±0.33 and the corresponding distance 843±^(138 119)pc. The luminosity mass of M67 is determined to be 1055_(μ⊙) from the luminosity function of the duster and an estimation of probable member binary systems. The virial mass is found to be 275_(μ⊙) based on the virial theorem and by using the intrinsic proper motion dispersion of the cluster that is directly taken from the solution of the distribution parameters in this paper. It is shown that there seems to be a mass segregation in both space and velocity for M67, although the effects are not significant.
出处
《天文学报》
CSCD
北大核心
1992年第4期427-435,共9页
Acta Astronomica Sinica
关键词
银河星团
位力质量
分层
open cluster—luminosity function—mass segregation
