Bw. Carney et al., DISCOVERY OF AN ALPHA-ELEMENT-POOR HALO STAR IN A SEARCH FOR VERY LOW-METALLICITY DISK STARS, The Astronomical journal, 114(1), 1997, pp. 363-375
We report [Fe/H] results for a sample of five high-velocity metal-poor
halo population stars and five comparably metal-poor stars thought to
have kinematics typical of an older, hotter disk population. We also
derive abundances of lithium, oxygen, magnesium, silicon, calcium, tit
anium, and barium for many of the stars. Four of the candidate disk po
pulation stars are found to be subgiants, and a re-evaluation of their
kinematics show that they have kinematics typical of the halo populat
ion. One star, G190-25, is confirmed to be a dwarf with thick disk-lik
e kinematics: U=-10, V=-80, W=-90 km s(-1). It is indistinguishable in
[X/Fe] from other metal-poor stars with higher velocities, however. T
he most interesting star is the high-velocity subgiant BD+80 degrees 2
45, which is found to have [[''alpha''/Fe]]=-0.29+/-0.02 despite its l
ow metallicity, [Fe/H]=-1.86. It is also extremely deficient in barium
, [Ba/Fe]approximate to-1.8, and has a large apogalacticon distance, o
ver 20 kpc. It has experienced a very different chemical history than
have other metal-poor stars found in the solar neighborhood. (C) 1997
American Astronomical Society.