Galactic Kinematics Derived From Hipparcos Proper Motions

Analyzing Hipparcos proper motions of 1352 O-B5 stars, we have found a clear stellar warping-motion that is a systematicrotation +3.8 ±1.1 kms^-1kpc^-1 of stars about the axis pointing to the galactic center in the sense of increasing the inclination of the HI warp, and a remarkably large galactic rotation of (V₀)_O-B5 = 268.7 ± 11.9kms^-1, compared with the IAU recommendation (V₀=220 ± 20kms^-1), given the galactocentric distance of the sun R0 = 8.5kpc.Combining Hipparcos proper motions and the radial velocity data, we have then studied the kinematics for 151 classical cepheids.The results show a contracting motion of the Galaxy in the solar neibourhood, ∂Vθ=∂θ/R-2.60 ± 1.07kms^-1kps^-1, which is along the solar circle.In the present paper, we have also analyzed proper motions of 21000 K-M giants, and again we found a large galacticrotation (V₀)_K-M = 252.6 ±9.5kms^-1.