On the Origin of Metal-poor Stars in the Solar Neighborhood
  We determined the ages, the kinematic parameters and Galactic orbital
parameters of six metal-poor (-2.4<[Fe/H]<-1 dex) F-type high proper motion
(HPM) stars to investigate their HPM nature and origin. For the kinematical
procedure, the astrometric data from the Gaia DR2 was used. High resolution
ELODIE spectra of the six dwarfs were also used to obtain accurate [Fe/H]
abundances and up-to-date [$\alpha$/Fe] abundances. The calculations for
stellar ages were based on Bayesian statistics, with the computed ages falling
in the range 9.5-10.1 Gyrs. On the basis of the metallicities and ages, six HMP
stars are members of halo (HD6755, HD84937, BD +42 3607) or members of the
low-metallicity tail of the thick disk (HD 3567, HD 194598, HD 201891).
However, Galactic orbital parameters suggest thin disk (HD 84937, HD 194598),
thick disk (HD 3567, HD 201891), and halo (HD 6755, BD +42 3607) population.
The dynamical analysis was also performed for the escape scenario from the
candidate GCs. The tidal disruption of a dwarf galaxy was also considered to be
as an alternative origin. HD 6755, HD 194598, and HD 3567 with their retrograde
orbital motions are likely candidate stars for a tidally disrupted dwarf galaxy
origin. However, HD 194598 relationship with NGC 6284 presents an interesting
case. Its encounter velocity is low (16+/-28 km/s) and their ages and
metallicities are very nearly consistent with each other at the 1$\sigma$
level. The rest of the HPM sample stars have a 4% to 18% probability of
encountering with selected GCs for 1.5 tidal radii. This indicates that a
globular cluster origin for the program stars is unlikely.
