CDROM/AJ/V113/P1711     RR Lyrae in NGC 6171 (Clement & Shelton 1997)
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The Structure of the Light Curves of the RR Lyrae Variables in the Oosterhoff
Type I Cluster NGC 6171
      Christine M. Clement and Ian Shelton
      <1997, AJ, 113, 1711>
      =1997AJ....113.1711C
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Abstract:
  CCD observations have been used to derive precise light curves and
  Fourier parameters for sixteen RR Lyrae variables in the Oosterhoff
  type I globular cluster NGC 6171. It is found that, for the RRab
  stars, the Fourier phase differences Phi_21, Phi_31 and Phi_41 all
  correlate with period, but the amplitude ratios R_21, R_31, and R_41
  do not. For the RRc stars, R_21, Phi_31, and Phi_41 correlate with
  period, but Phi_21, R_31, and R_41 do not. It is also found that a
  plot of R_21 against Phi_21 is a useful tool for distinguishing
  between RRc and RRab stars, regardless of color or chemical
  composition. Simon's method that relates physical properties of RRc
  stars to the pulsation period and Fourier phase parameter Phi_31
  has been used to determine the mass, luminosity, temperature and a
  helium parameter for the RRc stars. A comparison with the parameters
  determined from CCD observations of RRc stars in six other galactic
  globular clusters indicates that mean masses and mean luminosities
  increase and mean temperatures and helium abundances decrease with
  decreasing cluster metal abundance. The formulae of Jurcsik & Kovacs
  for relating Fourier parameters of RRab stars to [Fe/H] and luminosity
  have been tested and the results are reasonable. (c) 1997 American
  Astronomical Society.

Description:
  The complete table caption from the printed paper follows:
  The Julian dates represent the time of mid-exposure. The first two digits
  of the JD are omitted in the table so that 49122.6408 actually represents
  JD 2449122.6408. The magnitudes are on the standard V system. There are
  observations for 16 stars included here. They are variables: 4, 6, 7, 8,
  9, 10, 12, 14, 15, 17, 18, 19, 20, 21, 23 and 24.

File Summary:
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File Name    Lrecl    Records   Explanations
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table8.dat      24       1987   Las Campanas observations for NGC 6171
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Byte-by-byte Description of file: table8.dat
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   Bytes Format  Units      Label       Explanations
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   1- 3   A3      ---       Var         Variable name
   4-15   D12.4   JD        JD          Julian date - 2400000
  16-24   F9.4    mag       V           V magnitude
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(End)                                             Lee Brotzman [ADS] 30-Oct-1997