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J/A+A/347/69       Abundances of halo early-type stars        (Rolleston+, 1999)
Early-type stars in the Galactic halo from the Palomar-Green Survey.
II: A sample of distant, apparently young Population I stars
       Rolleston W.R.J., Hambly N.C., Keenan F.P., Dufton P.L., Saffer R.A.
      <Astron. Astrophys. 347, 69 (1999)>
      =1999A&A...347...69R      (SIMBAD/NED BibCode)
ADC_Keywords: Stars, early-type ; Equivalent widths ; Abundances

Keywords: stars: abundances - stars: atmospheres - stars: early-type -
          stars: kinematics

Abstract:
    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.
Objects:
    ----------------------------------------------------------
       RA   (2000)   DE      Designation(s)
    ----------------------------------------------------------
    08 58 21.0   +29 12 12   PG 0855+294
    09 37 04.0   +14 18 24   PG 0934+145
    09 58 14.4   +28 52 26   PG 0955+291
    12 07 57.4   +22 31 47   PG 1205+228
    22 21 59.1   +09 37 31   PG 2219+094
    22 32 08.5   +10 14 25   PG 2229+099
    23 48 22.4   +24 23 06   PG 2345+241
    ----------------------------------------------------------

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table4.dat        74       17   Equivalent width for the non-diffuse helium and
                                  metal lines (PG 0855+294 to PG 2219+094)
table5.dat        38       61   Equivalent width for the non-diffuse helium and
                                  metal lines (PG 2229+099 and PG 2345+241)


Byte-by-byte Description of file: table4.dat

   Bytes Format Units   Label    Explanations

   1-  7  F7.2  0.1nm   Line     Wavelength of spectral line
  10- 15  A6    ---     Species  Ionization stage of element
  18- 20  I3    0.1pm   EW0855   ? Equivalent width for PG 0855+294
  22- 26  F5.2  ---     A0855    ? LTE abundances for PG 0855+294 in 12+log(X/H)
  30- 32  I3    0.1pm   EW0934   ? Equivalent width for PG 0934+145
  34- 38  F5.2  ---     A0934    ? LTE abundances for PG 0934+145 in 12+log(X/H)
  42- 44  I3    0.1pm   EW0955   ? Equivalent width for PG 0955+291
  46- 50  F5.2  ---     A0955    ? LTE abundances for PG 0955+291 in 12+log(X/H)
  54- 56  I3    0.1pm   EW1205   ? Equivalent width for PG 1205+228
  58- 62  F5.2  ---     A1205    ? LTE abundances for PG 1205+228 in 12+log(X/H)
  66- 68  I3    0.1pm   EW2219   ? Equivalent width for PG 2219+094
  70- 74  F5.2  ---     A2219    ? LTE abundances for PG 2219+094 in 12+log(X/H)


Byte-by-byte Description of file: table5.dat

   Bytes Format Units   Label    Explanations

   1-  7  F7.2  0.1nm   Line     Wavelength of spectral line
  10- 15  A6    ---     Species  Ionization stage of element
  18- 20  I3    0.1pm   EW2229   ? Equivalent width for PG 2229+099
  22- 26  F5.2  ---     A2229    ? LTE abundances for PG 2229+099 in 12+log(X/H)
  30- 32  I3    0.1pm   EW2345   ? Equivalent width for PG 2345+241
  34- 38  F5.2  ---     A2345    ? LTE abundances for PG 2345+241 in 12+log(X/H)


Acknowledgements: Robert Rolleston 


References:
     Hambly et al., Paper I.          1997ApJS..111..419H
(End)                                         Patricia Bauer [CDS]   29-Apr-1999