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J/A+AS/117/317 uvby-beta photometry of metal-poor stars. VIII. (Schuster+ 1996)
uvby-β photometry of high-velocity and metal-poor stars.
VIII. Stars of very low metal abundance.
      Schuster W.J., Nissen P.E., Parrao L., Beers T.C., Overgaard L.P.
     <Astron. Astrophys. Suppl. Ser. 117, 317 (1996)>
     =1996A&AS..117..317S      (SIMBAD/NED BibCode)
ADC_Keywords: Stars, high-velocity ; Stars, metal-deficient ;
              Photometry, uvby, beta ; Abundances, [Fe/H]
Keywords: stars: abundances - stars: distances - stars: fundamental parameters -
          dust, extinction - Galaxy: evolution - Galaxy: halo

Abstract:
    A catalogue of uvby-β photometry for 87 of the turn-off and
    subgiant stars from the HK survey of Beers et al.
    (1992AJ....103.1987B, BPSII) is given. Most of these stars have
    [Fe/H]≤2.5. These photometric data have been taken and reduced using
    the same techniques as in our previous two uvby-β catalogues
    (Schuster et al., 1989, Cat. II/180 and Schuster et al., 1993, Cat.
    J/A+AS/97/951). An error analysis has been made; typical mean
    observational errors for a star with V=14.2m are 0.008, 0.007, 0.011,
    0.010 and 0.012 in V, (b-y), m1, c1 and β, respectively. Our
    photometric data are also compared to the UBV photometry and spectral
    indices from the HK survey; satisfactory agreement is found indicating
    good quality for the two data sets. The stars are classified in
    reddening-free diagrams of the uvby-β system; several of the
    stars are found to have been mis-classified in the HK survey. Two
    metal-poor supergiants, three (possibly four) horizontal branch stars,
    one blue subluminous star and two stars with ambiguous photometry have
    been identified. Stellar parameters, such as E(b-y), MV,
    δMV, and Teff, plus error estimates for these parameters,
    are provided using our photometric calibrations. Although all stars
    have galactic latitudes |b|≥30° many of them are significantly
    reddened with E(b-y) ranging from 0.02 to 0.15. The average reddening
    towards the South Galactic Pole region, b←60°, is
    E(b-y)=0.027±0.004 corresponding to E(B-V)=0.036±0.005 in contrast
    to the low value of E(B-V)∼0.01 derived from the Burstein & Heiles
    (1982AJ.....87.1165B) maps. The stars are analyzed in the (b-y)0,
    [Fe/H] diagram, and individual ages estimated using the isochrones of
    VandenBerg & Bell (1985ApJS...58..561V) and of Bergbusch & VandenBerg
    (1992ApJS...81..163B). These very metal-poor stars are found to be
    coeval, within 1-2Gyr, with the halo and thick-disk stars studied
    previously, with a mean age in excess of 18Gyr. Several blue
    "thick-disk" stars, which are perhaps analogous to the "blue
    metal-poor" stars of Preston et al. (1994, Cat. J/AJ/108/538), have
    been identified.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1            80       87   The standard uvby-β catalogue for the 87 BPSII
                              (Beers et al., 1992AJ....103.1987B) stars
table2            70       86   Stellar parameters for the 86 VMP stars.


See also:
        II/180 : uvby-beta photometry of metal-poor stars. III. (Schuster+ 1989)
 J/A+AS/97/951 : uvby-beta photometry of metal-poor stars.  VI. (Schuster+ 1993)
 J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)
 J/A+A/422/527 : Metal-poor stars uvby-beta photometry. X. (Schuster+, 2004)
 J/A+A/445/939 : Metal-poor stars uvby-beta photometry. XI. (Schuster+, 2006)


Byte-by-byte Description of file: table1

   Bytes Format Units   Label     Explanations

   1-  9  A9    ---     Star      Star designation according to BPSII
                                   (Beers et al., 1992AJ....103.1987B)
  11- 16  F6.3  mag     Vmag      V magnitude
  18- 22  F5.3  mag     b-y       b-y colour index
  24- 29  F6.3  mag     m1        m1 colour index
  31- 35  F5.3  mag     c1        c1 colour index
      37  I1    ---     o_b-y     Number of independent uvby observations
  39- 43  F5.3  mag     beta      beta colour index
      45  I1    ---     o_beta    Number of independent beta observations
  47- 80  A34   ---     Note      Note


Byte-by-byte Description of file: table2

   Bytes Format Units   Label     Explanations

   1-  9  A9    ---     Star      Star designation according to BPSII
                                   (Beers et al., 1992AJ....103.1987B)
  11- 16  F6.3  mag     E(b-y)    ? Reddening
  18- 22  F5.3  mag     e_E(b-y)  ? rms uncertainty on E(b-y)
  24- 28  F5.2  [Sun]   [Fe/H]c   ? Spectroscopic metallicity
  30- 34  F5.2  [Sun]   [Fe/H]p   ? Photometric metallicity
      35  A1    ---    u_[Fe/H]p  Uncertainty flag on [Fe/H]p
  37- 40  F4.2  [Sun]  e_[Fe/H]p  ? rms uncertainty on [Fe/H]p
  42- 45  F4.2  mag     MV        ? Absolute V magnitude
  47- 50  F4.2  mag     e_MV      ? rms uncertainty on MV
  52- 56  F5.2  mag     dMV       ? Evolutionnary correction δMV
                                     (See Nissen et al., 1991A&A...251..457N)
  58- 61  F4.2  mag     e_dMV     ? rms uncertainty on dMV
  63- 66  I4    K       Teff      ? Effective temperature
  68- 70  I3    K       e_Teff    ? rms uncertainty on Teff


History: Prepared via OCR at CDS.


References:
   Schuster at al., Paper I.   1988A&AS...73..225S
   Schuster at al., Paper II.  1989A&A...221...65S
   Schuster at al., Paper III. 1989A&A...222...69S, Cat. II/180
   Allen et al., Paper IV.     1991A&A...244..280A
   Nissen et al., Paper V.     1991A&A...251..457N
   Schuster et al. Paper VI.   1993A&AS...97..951S, Cat. J/A+AS/97/951
   Marquez et al., Paper VII.  1994A&AS..108..341M
   Schuster at al., Paper IX.  1997A&A...319..796S
   Schuster at al., Paper X.   2004A&A...422..527S, Cat. J/A+A/422/527
   Schuster at al., Paper XI.  2006A&A...445..939S, Cat. J/A+A/445/939
(End)                           James Marcout, Patricia Bauer [CDS]  12-Sep-1997