Abstract

ARELLANO FERRO, A.; AHUMADA, J. A.; CALDERON, J. H.  and  KAINS, N.. Fourier decomposition of RR Lyrae ligth curves and the SX Phe population in the central region of NGC 3201. Rev. mex. astron. astrofis [online]. 2014, vol.50, n.2, pp.307-322. ISSN 0185-1101.

CCD time-series observations of the central region of the globular cluster NGC 3201 were obtained with the aim of performing the Fourier decomposition of the light curves of the RR Lyrae stars present in that field. This procedure gave the mean values, for the metallicity, of [Fe/H]_zw = −1.483 ± 0.006 (statistical) ±0.090 (systematic), and for the distance, 5.000 ± 0.001 kpc (statistical) ±0.220 (systematic). The values found from two RRc stars are consistent with those derived previously. The differential reddening of the cluster was investigated and individual reddenings for the RR Lyrae stars were estimated from their V − I curves. We found an average value of E(B − V) = 0.23 ± 0.02. An investigation of the light curves of stars in the blue straggler region led to the discovery of three new SX Phe stars. The period-luminosity relation of the SX Phe stars was used for an independent determination of the distance to the cluster and of the individual reddenings. We found a distance of 5.0 kpc.

Keywords : globular clusters [individual]; globular clusters [(NGC 3201)]; stars [variables]; stars [RR Lyrae].

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