ADC/CDS Standard Document for Catalog:
/catalogs/3/3176/

IMPORTANT NOTICE:

Superseded         RR Lyrae Metallicities (Layden 1994)
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RR Lyrae data II. The Metallicities and Kinematics of Local RR Lyraes
    Layden A.C.
    <AJ in press (1994)>
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ADC_Keywords: Abundances ; Abundances, [Fe/H] ; Radial velocities ; Stars,
    population II ; Stars, variable

Description:
   This catalog presents metal abundance, distance and radial velocity data
   on a sample of 302 ab-type RR Lyrae variables within about 2.5 kpc of the
   Sun. The metal abundance information was obtained from low-medium
   resolution spectra, using the pseudo-equivalent widths of the Ca II K line
   and the the H-delta, H-gamma and H-beta lines. The technique employed was
   similar to Preston's (1959) Delta-S method, though significant differences
   exist; see the source reference for details. The data were calibrated to
   the Zinn & West (1984) globular cluster abundance scale.
  
   The photometry employed in the distance determinations was primarily taken
   from the General Catalog of Variable Stars (1985, hereafter GCVS4).
   Exceptions are noted in column 29; the letters match the footnotes in
   Table 10 of Layden (1994). The minimum and maximum light photometry, and
   rise-time were combined following Barnes & Hawley (1986) to give an
   estimate of the intensity-averaged magnitude, i.e. the magnitude the star
   would have if it were not variable. When the GCVS4 quoted magnitudes in
   passbands other than V, the GCVS4 magnitudes were transformed to the V
   passband using the relations established in Layden (1994). The
   interstellar absorption estimates are from Burstein & Heiles (1982),
   modified by a simple dust-distribution model. The distances were
   computed assuming the Mv(RR)-[Fe/H] relation of Carney, Storm & Jones
   (1992).
  
   Radial velocities were measured from the spectra via cross-correlation
   with secondary velocity standards. The velocities from the individual
   spectra were fit with a standard radial velocity curve in the (phase,
   velocity) plane, to give an estimate of the systemic (center of mass)
   velocity of each star. The error in this value was estimated from the
   scatter about the best-fit velocity curve, and the quality of the spectra
   employed. Other methods were used to combine the individual velocities
   when the situation demanded (cm = 2,3 in column 70; see Layden (1994) for
   details). The observed velocities were combined with values from the
   literature to produce a final, best estimate of the systemic radial
   velocity of each star, and its error.
  
References:
   Barnes, T.G.III & Hawley, S. 1986, ApJL, 307, L9
   Burstein, D. & Heiles, C. 1982, AJ, 87, 1165
   Carney, B.W., Storm, J. & Jones, R.V. 1992, ApJ, 386, 663
   Kholopov, P.N. 1985, General Catalog of Variable Stars, 4th Edition,
     (Moscow: Nauka Publishing House)
   Preston, G.W. 1959, ApJ, 130, 507
   Zinn, R.J. & West, M.J. 1984, ApJS, 55, 45
   peculiar stars).               

See also:
   Superseded by journal table J/AJ/108/1016:

J/AJ/108/1016      Kinematics of local RR lyrae stars. I. (Layden, 1994)
   at URL ftp://adc.astro.umd.edu/pub/adc/archives/journal_tables/AJ/108/1016


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