Early-type stars in the Galactic halo from the Palomar-Green Survey. II: A sample of distant, apparently young Population I stars J/A+A/347/69 J/A+A/347/69 Abundances of halo early-type stars Early-type stars in the Galactic halo from the Palomar-Green Survey. II: A sample of distant, apparently young Population I stars W R J Rolleston N C Hambly F P Keenan P L Dufton R A Saffer Astron. Astrophys. 347 69 1999 1999A&A...347...69R Abundances Equivalent widths Stars, early-type stars: abundances stars: atmospheres stars: early-type stars: kinematics We present echelle (R~40,000) spectroscopic observations for a sample of apparently normal, high Galactic latitude, early-type stars drawn from the Palomar-Green Survey. The metal-line spectra show evidence for rotational velocity broadening with values of vsini<=300km/s. In conjunction with Kurucz model atmospheres, we derive stellar photospheric abundances that are consistent with a Population I chemical composition; differential abundances with respect to Galactic disk Population I stars indicate no abundance differences outside the estimated errors. From a comparison of the derived atmospheric parameters with recent theoretical evolutionary models, we derive distance and age estimates for individual stars. Using kinematical considerations, we conclude that all these objects are `runaway' stars, formed in the Galactic disk and subsequently ejected, possibly by supernovae explosions or dynamical interactions.
PG 0855+29408 58 21.0+29 12 12 PG 0934+14509 37 04.0+14 18 24 PG 0955+29109 58 14.4+28 52 26 PG 1205+22812 07 57.4+22 31 47 PG 2219+09422 21 59.1+09 37 31 PG 2229+09922 32 08.5+10 14 25 PG 2345+24123 48 22.4+24 23 06
 Equivalent width for the non-diffuse helium and metal lines (PG 0855+294 to PG 2219+094) Line Wavelength of spectral line 0.1nm Species Ionization stage of element --- EW0855 Equivalent width for PG 0855+294 0.1pm A0855 LTE abundances for PG 0855+294 in 12+log(X/H) --- EW0934 Equivalent width for PG 0934+145 0.1pm A0934 LTE abundances for PG 0934+145 in 12+log(X/H) --- EW0955 Equivalent width for PG 0955+291 0.1pm A0955 LTE abundances for PG 0955+291 in 12+log(X/H) --- EW1205 Equivalent width for PG 1205+228 0.1pm A1205 LTE abundances for PG 1205+228 in 12+log(X/H) --- EW2219 Equivalent width for PG 2219+094 0.1pm A2219 LTE abundances for PG 2219+094 in 12+log(X/H) --- Equivalent width for the non-diffuse helium and metal lines (PG 2229+099 and PG 2345+241) Line Wavelength of spectral line 0.1nm Species Ionization stage of element --- EW2229 Equivalent width for PG 2229+099 0.1pm A2229 LTE abundances for PG 2229+099 in 12+log(X/H) --- EW2345 Equivalent width for PG 2345+241 0.1pm A2345 LTE abundances for PG 2345+241 in 12+log(X/H) --- Patricia Bauer CDS 1999Apr29Robert Rolleston <R.Rolleston@Queens-Belfast.AC.UK> J_A+A_347_69.xml