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J/MNRAS/384/1444  Vr light curves of NGC 5466 RR Lyrae   (Arellano Ferro+, 2008)

CCD Photometry of the globular cluster NGC 5466. RR Lyrae light curve decomposition and the distance scale. Arellano Ferro A., Rojas Lopez V., Giridhar S., Bramich D.M. <Mon. Not. R. Astron. Soc. 384, 1444 (2008)> =2008MNRAS.384.1444A
ADC_Keywords: Clusters, globular ; Stars, variable ; Photometry, CCD Keywords: globular clusters: NGC 5466 - variable stars: RR Lyrae, SX Phe - eclipsing binaries Abstract: We report the results of CCD V and r photometry of the globular cluster NGC 5466. The difference image analysis technique adopted in this work has resulted in accurate time series photometry even in crowded regions of the cluster enabling us to discover five probably semi-regular variables. We present new photometry of three previously known eclipsing binaries and six SX Phe stars. The light curves of the RR Lyrae stars have been decomposed in their Fourier harmonics and their fundamental physical parameters have been estimated using semi-empirical calibrations. The zero points of the metallicity, luminosity and temperature scales are discussed and our Fourier results are transformed accordingly. The average iron abundance and distance to the Sun derived from individual RR Lyrae stars, indicate values of [Fe/H]=-1.91±0.19 and D=16.0±0.6kpc, or a true distance modulus of 16.02±0.09mag, for the parent cluster. These values are respectively in the Zinn & West metallicity scale and in agreement with recent luminosity determinations for the RR Lyrae stars in the LMC. The MV-[Fe/H] relation has been recalibrated as MV=+(0.18±0.03)[Fe/H]+(0.85±0.05) using the mean values derived by the Fourier technique on RR Lyrae s tars in a family of clusters. This equation predicts MV=0.58mag for [Fe/H]=-1.5, in agreement with the average absolute magnitude of RR Lyrae stars calculated from several independent methods. The M_V-[Fe/H] relationship and the value of [Fe/H] have implications on the age of the globular clusters when determined from the magnitude difference between the horizontal branch and the turn off point (HB-TO method). The above results however would not imply a change in the age of NGC 5466, of 12.5±0.9Gyr, estimated from recent isochrone fitting. Objects: ---------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------- 14 05 27.4 +28 32 04 NGC 5466 = C 1403+287 ---------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file stars.dat 99 35 Star list and ephemerides of the known RR Lyrae table3.dat 30 2035 Standard V magnitudes of RR Lyrae stars in NGC 5466 table4.dat 30 1998 Instrumental r magnitudes of RR Lyrae stars table5.dat 30 462 Standard V magnitudes of new variables in NGC 5466 table6.dat 30 896 Standard V magnitudes of 3 eclipsing binaries and 6 SX Phoenicis stars
See also: V/97 : Updated 3rd Cat Variable Stars in Globular Clusters (Clement+ 1997) Byte-by-byte Description of file: stars.dat
Bytes Format Units Label Explanations
1- 4 A4 --- Star Variable name 6- 25 A20 --- SName Simbad name (if exist) 27- 35 F9.7 d Per ? Period 37 I1 --- r_Per [1/4]? Period reference (1) 39- 49 F11.3 d Epoch ? Epoch 51- 58 F8.6 d PerN ? New period 60- 70 F11.3 d EpochN ? New epoch 72- 95 A24 --- VType Type of variable 97- 99 A3 --- Tables Number of the table(s) with photometry
Note (1): Period reference as follows: 1 = Sawyer Hogg, 1973PDDO....3....6S (See Cat. V/97 2 = Corwin et al., 1999AJ....118.2875C 3 = McCarthy & Nemec, 1997ApJ...482..203M 4 = this paper
Byte-by-byte Description of file: table*.dat
Bytes Format Units Label Explanations
1- 4 A4 --- Star Variable number identification 6- 17 F12.4 d HJD Heliocentric Julian Date 21 A1 --- Band [Vr] Band for the magnitude 25- 30 F6.3 mag mag Standard V or r magnitude
Acknowledgements: Armando Arellano Ferro, armando(at)astroscu.unam.mx
(End) Patricia Vannier [CDS] 05-Mar-2008
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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