Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/5039
Title: CCD time-series photometry of the globular cluster NGC 5053: RR Lyrae, Blue Stragglers and SX Phoenicis stars revisited
Authors: Arellano Ferro, A
Giridhar, S
Bramich, D. M
Keywords: Stars: Horizontal Branch
Stars: Individual: RR Lyrae
Globular Clusters: Individual: NGC 5053
Issue Date: Feb-2010
Publisher: Blackwell Publishing
Citation: Monthly Notices of the Royal Astronomical Society, Vol. 402, No.1, pp. 226 – 244
Abstract: We report the results of CCD V, r and I time-series photometry of the globular cluster NGC 5053. New times of maximum light are given for the eight known RR Lyrae stars in the field of our images, and their periods are revised. Their V light curves were Fourier decomposed to estimate their physical parameters. A discussion on the accuracy of the Fourier-based iron abundances, temperatures, masses and radii is given. New periods are found for the five known SX Phe stars, and a critical discussion of their secular period changes is offered. The mean iron abundance for the RR Lyrae stars is found to be [Fe/H] ~ -1.97 +/- 0.16 and lower values are not supported by the present analysis. The absolute magnitude calibrations of the RR Lyrae stars yield an average true distance modulus of 16.12 +/- 0.04 or a distance of 16.7 +/- 0.3 kpc. Comparison of the observational colour magnitude diagram (CMD) with theoretical isochrones indicates an age of 12.5 +/- 2.0 Gyr for the cluster. A careful identification of all reported blue stragglers (BS) and their V, I magnitudes leads to the conclusion that BS12, BS22, BS23 and BS24 are not BS. On the other hand, three new BS are reported. Variability was found in seven BS, very likely of the SX Phe type in five of them, and in one red giant star. The new SX Phe stars follow established Period-Luminosity relationships and indicate a distance in agreement with the distance from the RR Lyrae stars.
URI: http://hdl.handle.net/2248/5039
ISSN: 0035-8711
Appears in Collections:IIAP Publications
Publications based on data from IAO, Hanle

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