New subdwarfs. II. Radial velocities, photometry, and preliminary space motions for 112 stars with large proper motion

Abstract

view Abstract Citations (242) References (68) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS New subdwarfs 2 Radial velocities, photometry and preleminary space motions for 112 stars with large proper motion. Sandage, A. Abstract Radial velocities have been measured for 112 stars of large proper motion selected from an unpublished photometric catalog which contains 300 new subdwarf candidates The accuracy of the radial velocities is generally better than ± 2 km sec'. Nine possible velocity variables have been found, four of which are almost certain cases. Two particularly interesting variables (G9- 16, G26-9) probably have blue subluminous companions which are brighter than white dwarfs but considerably fainter than main- sequence stars. Space motions for all stars are shown in a Bottlinger diagram. The asymmetrical-drift velocity and the dispersions in U and W increase systematically with decreasing metal abundance for the entire range of ultraviolet excess values from ô = 0.00 to ~ = 0.31 mag The results are interpreted in terms of a chemical gradient perpendicular to the galactic plane. Many globular-clusterlike subgiants are present in the material. Candidates are listed to aid future spectroscopic studies. The existence of subdwarfs possessing high angular momentum which lead the Sun in its galactic rotational velocity seems to be established. There may be a systematic variation of metal abundance with increasingly positive V velocity, but more subdwarfs of this type are needed to establish the correlation. Candidates can be found in proper-motion catalogs from among stars whose proper-motion angles are directed away from the high-velocity antapex. A procedure is given to correct observed ultraviolet excess values for stars with the same metal abun- dance but of different colors for the effect of the guillotine Publication: The Astrophysical Journal Pub Date: December 1969 DOI: 10.1086/150271 Bibcode: 1969ApJ...158.1115S full text sources ADS | data products SIMBAD (113) GCPD (1) Related Materials (5) Part 1: 1964ApJ...139..442S Part 3: 1981AJ.....86.1643S Part 4: 1986AJ.....91.1140S Part 5: 1986AJ.....91.1189F Part 6: 1987AJ.....93...74S