J/other/RMxAA/42.75 CCD RV light curve of M15 RR Lyrae (Arellano Ferro+, 2006)
CCD Photometry of the Globular Cluster M15:
RR Lyrae Fourier Decomposition and Physical Parameters.
Arellano Ferro A., Garcia Lugo G., Rosenzweig P.
<Rev. Mex. Astron. Astrofis., 42, 75-87 (2006)>
=2006RMxAA..42...75A 2006RMxAA..42...75A
ADC_Keywords: Clusters, globular ; Stars, variable ; Photometry, CCD
Keywords: globular clusters (M15) - Stars: variables: RR Lyrae -
stars: horizontal branch
Abstract:
Results of CCD photometry using V and R filters are reported for 33
RR Lyrae stars in M15. Applying the approach of Fourier decomposition
of the light curves, the physical parameters of the type RRab and RRc
variables were estimated. The cluster is Oosterhoff type II and the
values for the iron content and distance are: [Fe/H]=-1.98±0.24 and
d=8.67±0.41kpc, respectively. The mean values of the physical
parameters determined for the RR Lyrae stars place the cluster
precisely into the sequences Oosterhoff type - metallicity and
metallicity - effective temperature, valid for globular clusters.
Evidences of evolution from the ZAHB are found for the RRc but not for
the RRab stars.
Description:
V and R images were obtained in 2000 and 2001, using the 1.5m
telescope of San Pedro Martit Observatory (SPM), in Baja California,
Mexico. A total of 129 and 127 images in the V and R filters,
respectively, were obtained during both seasons and distributed in two
fields of the cluster. The instrumental magnitudes were obtained using
the PSF function, calculated for each frame from relatively isolated
and well exposed stars, in the field of the cluster. The
transformation to the standard system was performed differentially,
relative to a group of standard stars in the observed fields of M15.
The accuracy of the photometry is estimated as ±0.031 and ±0.019
for the V and R filters respectively.
Objects:
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RA (2000) DE Designation(s)
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21 29 58.4 +12 10 01 M15 = NGC 7078
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 24 1240 Johnson V CCD photometry of RR Lyraes in M15
table2.dat 24 1171 Johnson R CCD photometry of RR Lyraes in M15
table4.dat 42 34 Ephemeris of the RR Lyrae stars in M15 used in
the present work
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See also:
J/AJ/110/704 : RR Lyrae Variables in M15 (Silbermann+ 1995)
J/ApJ/602/264 : Proper motions and radial velocities in M15 (Mcnamara+, 2004)
Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Star Variable number in M15,
Cl* NGC 7078 Saw VNN in Simbad (G1)
5 A1 --- Band [VR] Johnson V or R band for magnitude
7- 12 F6.3 mag mag Johnson V or R magnitude
14- 24 F11.3 d HJD Heliocentric Julian Date
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Star Variable number in M15,
Cl* NGC 7078 Saw VNN in Simbad (G1)
5- 9 A5 --- Type RR Lyrae type
11- 21 F11.3 d HJD Epoch of maximum light
23- 31 F9.7 --- P0 Fundamental period
32 A1 --- u_P0 [?] Uncertainty flag on P0
33- 42 F10.8 --- P1 ? Second period for double mode or RRd pulsator
44 A1 --- r_P0 [abc] Reference for Periods (1)
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Note (1): References for Periods as follows:
a = Period calculated in the present work
b = Period taken from Clement
(2002, http://www.astro.utoronto.ca/~cclement/read.html)
c = Period taken from Cox et al. (1983ApJ...266...94C 1983ApJ...266...94C)
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Global notes:
Note (G1): These stars have no position in Simbad.
The finding charts are in Figs 1 & 2 of the paper.
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Acknowledgements: Armando Arellano Ferro, armando(at)astroscu.unam.mx
(End) A. Arellano Ferro [IAUNAM, Mexico], Patricia Vannier [CDS] 31-Mar-2006