Issue |
Astron. Astrophys. Suppl. Ser.
Volume 120, Number 1, November II 1996
|
|
---|---|---|
Page(s) | 139 - 152 | |
DOI | https://doi.org/10.1051/aas:1996280 | |
Published online | 15 November 1996 |
The optical gravitational lensing experiment. Variable stars in globular clusters. I. Fields 5139A-C in ω Centauri*
1
Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warsaw, Poland
2
Carnegie Observatories, Las Campanas Observatory, Casilla 601, La Serena, Chile
3
Department of Astronomy, University of Michigan, 821 Dennison Bldg., Ann Arbor, MI 48109-1090, U.S.A.
Send offprint request to: J. Kaluzny
Received:
3
January
1996
Accepted:
15
April
1996
Three fields covering the central part of the globular cluster
ω Cen were surveyed in a search for variable stars.
We present V-band light curves for 39 periodic variables: 24 SX Phe
stars, 7 contact binaries, 5 detached or semi-detached binaries, and
3 likely spotted variables (FK Com or RS CVn type stars). Only 2 of these
variables were previously known. All SX Phe stars and all contact
binaries from our sample belong to blue stragglers.
Observed properties of these stars are consistent with their
cluster membership. Of particular interest is detection of two
well detached binaries with periods P=1.50 day and P=2.47 day.
Further study of these two binaries can provide direct information about
properties of turnoff stars in ω Cen.
An incomplete light curve of a Mira variable known as was obtained.
We present V vs.
color-magnitude diagrams for the monitored
part of the cluster.
Key words: globular clusters: individual: NGC 5139 / star: variables: other / blue stragglers / binaries: eclipsing / HR diagram
© European Southern Observatory (ESO), 1996