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Astron. Astrophys. 358, 547-552 (2000)
Variable stars in the globular cluster M53
G. Kopacki
Wroc
aw University Observatory, Kopernika 11, 51-622 Wrocaw, Poland (kopacki@astro.uni.wroc.pl)
Received 1 December 1999 / Accepted 8 February 2000
Abstract
We present the results of the search for variable stars in the
central region of rather poorly studied globular cluster M53. We have
obtained good quality light curves of the 23 previously known RR Lyrae
stars in this cluster. Periods of four of them have been determined
for the first time. One RR Lyrae variable till now classified as a
Bailey type RRc, turned out to be type RRab. We have also confirmed
the variability of ten RR Lyrae candidates discovered by Kravtsov
(1990) and derived their periods. Moreover, we have found four new
variables of this type in the core of the cluster. Altogether, the
light curves have been obtained for 37 RR Lyrae stars. The total
number of known RR Lyrae stars in M53 equals now to 59, 29 of them
being of type RRab and remaining 30 of RRc. The mean period of all
known RRab variables in M53 amounts to
0.65![[FORMULA]](img1.gif)
0.07 d, and the average period for
RRc variables is equal to 0.360.04 d.
Mean V magnitudes and ranges of variations have been derived
for 19 RR Lyrae stars. We also report the discovery of variations in
six cluster bright giants. For these stars, however, our observations
are not sufficient to state whether the variability is periodic or
not.
Key words: stars:
Population II 
stars: variables:
general
Galaxy: globular clusters: individual: M53
Contents
- 1. Introduction
- 2. Observations and reductions
- 3. Identification of the variables
- 4. Results
- Acknowledgements
- References
© European Southern Observatory (ESO) 2000
Online publication: June 8, 2000
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