Maximum Likelihood Estimation Of The Kinematic Properties Of Open Cluster System

Some studies about open cluster system,such as spatial distribution and kinematic properties,are presented. Furthermore, kinematic properties of the Galaxy including solar motion,Galactic differential rotation,Galactic radial motion and velocity ellipsoid axis of open cluster system in the solar vicinity are studied with their parameters derived.First,current research of kinematic properties of the Galaxy as well as their latest results are reviewed.Second,an updated,most complete catalogue of 209 open clusters with galactic longitude,galactic latitude,heliocentric distance,age,absolute proper motion and radial velocity data as well as 41 open cluster only with radial velociyty data is compiled.Also,the spatial distribution of the open cluster system is studied. Last,as the main content of the thesis,the maximum-likehood analysis are applied to several groups of open cluster system divided according to heliocentric distance and age. The kinematic parameters of the Galaxy are derived,compared and discussed. Young open clusters of sample 1,2 with heliocentricdistance between O.Skpc and 2.0kpc are employed to determine kinematic properties. Solar-motion components are (u0,v0,w0) = (-16.4 ±0.8, -10.5 ±1.1, -1.9 ±1.7) km/s;Oort constants and Galactic radial motion parameters are(,4,5)=(14.8 ±1.0, -13.0 ±2.7)km/s/kpc and (C,D)=(1.5± 0.7, 1.2 ±1.5)km/s/kpc respectively; velocity ellipsoidare ( σ1,σ2 ,σ3) = (17.0 ±0.7, 12.2± 0.9, 8.0 ±1.3) km/s.