J/AJ/113/1711 RR Lyrae in NGC 6171 (Clement+ 1997)
The structure of the light curves of the RR Lyrae variables in the Oosterhoff
type I cluster NGC 6171
Clement C.M., Shelton I.
<Astron. J. 113, 1711 (1997)>
=1997AJ....113.1711C 1997AJ....113.1711C
ADC_Keywords: Stars, variable ; Magnitudes ; Clusters, globular
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 φ21, φ31 and
φ41 all correlate with period, but the amplitude ratios R21,
R31, and R41 do not. For the RRc stars, R21, φ31, and
φ41 correlate with period, but φ21, R31, and R41 do
not. It is also found that a plot of R21 against φ21 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 φ31 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 (1996, Cat. J/A+A/312/111) 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 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 (Cl* NGC 6171 DICK VNN, NN = 1 to 24, in Simbad database).
Objects:
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RA (2000) DE Designation(s)
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16 32 31.8 -13 03 13 NGC 6171 = M 107 = C 1629-129
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
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 --- Vname Variable name, as in Dickens, (1970ApJS...22..249D 1970ApJS...22..249D)
Cl* NGC 677 DICK in Simbad
5- 16 F12.4 JD JD Julian date
18- 24 F7.4 mag Vmag V magnitude
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Origin: AAS CD-ROM series, Volume 9, 1997 Lee Brotzman [ADS] 30-Oct-1997
(End) [CDS] 04-Feb-1998