Kinematics of Hipparcos visual binaries. II. Stars with ground-based orbital solutions.
BARTKEVICIUS A. and GUDAS A.
Abstract (from CDS):
This paper continues kinematical investigations of the Hipparcos visual binaries with known orbits. A sample, consisting of 804 binary systems with orbital elements determined from ground-based observations, is selected. The mean relative error of their parallaxes is about 12% and the mean relative error of proper motions is about 4%. However, even 41% of the sample stars lack radial velocity measurements. The computed Galactic velocity components and other kinematical parameters are used to divide the stars with known radial velocities into kinematical age groups. The majority (92%) of binaries from the sample are thin disk stars, 7.6% have thick disk kinematics and only two binaries have halo kinematics. Among them, the long-period variable Mira Ceti has a very discordant Hipparcos and ground-based parallax values. From the whole sample, 60 stars are ascribed to the thick disk and halo population. There is an urgent need to increase the number of the identified halo binaries with known orbits and substantially improve the situation with radial velocity data for stars with known orbits.
stars: binaries: visual - stars: kinematics - stars: Population II
VizieR on-line data:
<Available at CDS (J/BaltA/11/153): tables 1 to 13>