Search for variable stars in the open cluster NGC 2539
Abstract
We present UBVI absolute and V-band time-series CCD photometric results for the intermediate-age open cluster NGC 2539. From the empirical zero-age main sequence and theoretical isochrone fitting in color-color and color-magnitude diagrams, we estimated the physical parameters of this cluster as follows: the color excess of E(B-V)=0.06 +/- 0.03, the distance modulus of (V-MV)0=10.2 +/- 0.1 and the age of log t = 8.8 ( ~ 630 Myr). By carefully examining the time-series images, we discovered seven new variable stars in the observed cluster field. Considering the light curves, periods and positions on the color-magnitude diagram, we classified them as five eclipsing binary stars, one delta Scuti star and one gamma Doradus candidate. The gamma Doradus candidate might not be a cluster member because it is located redder by about Delta (B-V) = 0.2 than the cool edge of gamma Doradus instability strip.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 2003
- DOI:
- 10.1051/0004-6361:20021704
- Bibcode:
- 2003A&A...399...99C
- Keywords:
-
- open clusters and association: individual: NGC 2539;
- stars: Hertzsprung-Russell (HR) and C-M diagrams -;
- stars: binaries: eclipsing