Metallicities and kinematics of G and K dwarfs

Abstract

We have developed a photometric abundance indicator for G and K dwarfs, based on accurate, spectroscopically determined abundances for G and K dwarfs of Morell, K\"allander and Butcher (1992) and Morell (1994). Broadband Cousins R-I photometry is used to estimate effective temperature and the Geneva b_1 colour to estimate line blanketing in the blue and hence abundance. Abundances can be derived in the range -2.0<[Fe/H]<0.5 for G0 to K3 dwarfs, with a scatter in [Fe/H] of 0.2 dex. We apply the method to a sample of Gliese catalog G and K dwarfs, and examine the metallicity and kinematic properties of the stars. The stars show the well established observational features of the disk, thick disk and halo in the solar neighbourhood. We find that the distribution of local K dwarf metallicity is quite similar to local G dwarfs, indicating that there is a ``K-dwarf'' as well as a G-dwarf problem.