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J/MNRAS/372/69    VR light curves of M2 variables    (Lazaro+, 2006)

CCD photometry of the globular cluster M2: RR Lyrae physical parameters and new variables Lazaro C., Arellano Ferro A., Arevalo A., Bramich D.M., Giridhar S., Poretti E. <Mon. Not. R. Astron. Soc., 372, 69-80 (2006)> =2006MNRAS.372...69L
ADC_Keywords: Clusters, globular ; Stars, variable ; Photometry, CCD Keywords: stars: horizontal branch - stars: Population II - stars: variables: other - globular clusters: individual: M2 Abstract: We report the results of CCD V and R photometry of the RR Lyrae stars in M2. The periodicities of most variables are revised and new ephemerides are calculated. Light-curve decomposition of the RR Lyrae stars was carried out and the corresponding mean physical parameters [Fe/H]=-1.47, Teff=6276K, logL=1.63L and MV=0.71 from nine RRab and [Fe/H]=-1.61, M=0.54M, Teff=7215K, logL=1.74L and MV=0.71 from two RRc stars were calculated. A comparison of the radii obtained from the above luminosity and temperature with predicted radii from non-linear convective models is discussed. The estimated mean distance to the cluster is 10.49±0.15kpc. These results place M2 correctly in the general globular cluster sequences for Oosterhoff type, mass, luminosity and temperature, all as a function of the metallicity. Mean relationships for M, logL/L, Teff and MV as a function of [Fe/H] for a family of globular clusters are offered. These trends are consistent with evolutionary and structural notions on the horizontal branch. Eight new variables are reported. Description: Time-series V and R photometry for the variable stars in M2 (NGC7089). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file stars.dat 52 42 Summary of observed stars (from table3) varphot.dat 39 3314 CCD time-series V and R photometry of 30 variables in M2 (NGC7089)
See also: J/AJ/117/2868 : BV photometry in M2 (NGC 7089) (Lee+, 1999) V/97 : Updated 3rd Cat Variable Stars in Globular Clusters (Clement+ 1997) : Christine Clement's Catalogue of Variable Stars in Galactic Globular Clusters Byte-by-byte Description of file: stars.dat
Bytes Format Units Label Explanations
1- 3 A3 --- VName Variable star number 5- 6 A2 --- RRt RR Lyr variability type (ab or c) (1) 9- 10 I2 h RAh Right Ascension J2000 (hours) 12- 13 I2 min RAm Right Ascension J2000 (minutes) 15- 19 F5.2 s RAs Right Ascension J2000 (seconds) 21 A1 --- DE- Declination J2000 (sign) 22- 23 I2 deg DEd Declination J2000 (degrees) 25- 26 I2 arcmin DEm Declination J2000 (minutes) 28- 31 F4.1 arcsec DEs Declination J2000 (seconds) 34- 41 F8.5 d Per Period (1) 44- 52 F9.3 d T0 ? Epoch (JD-2400000) (1)
Note (1): only for stars V35 to V42 studied here. The positions and periods for stars 1 to 34 are from Christine Clement's page for M2 at:
Byte-by-byte Description of file: varphot.dat
Bytes Format Units Label Explanations
1- 3 A3 --- VName Variable star ID (V35 to V42) 5 A1 --- Filter [VR] Observation filter 7- 19 F13.5 d HJD Heliocentric Julian date at mid-exposure 21- 26 F6.3 mag magst ?=0.000 Standard magnitude 28- 33 F6.3 mag maginst Instrumental magnitude 35- 39 F5.3 mag e_maginst Magnitude uncertainty (standard or instrumental)
Acknowledgements: Daniel Bramich, dbramich(at)
(End) Daniel Bramich [ESO, Germany], Patricia Vannier [CDS] 22-Feb-2013
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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