Photometric analysis of a blue straggler eclipsing binary in the old open cluster NGC 2141

To understand the formation mechanism of blue stragglers in open clusters, we conducted a photometric analysis for a blue straggler eclipsing binary in the old open cluster NGC 2141. By using the least square fitting of times of minima, we derived the ephemeris and redetermined the orbital period of this system to be 0.6227 d. We have also done a photometric analysis for light curve with the Wilson-Devinney Code (2003). The photometric solutions reveal a semi-detached binary with the secondary component filling its Roche lobe. The photometric mass ratio M (2)/M (1) (secondary/primary) was determined to be 0.190 +/- 0.002 and the ratio of V-band luminosity L (2)/L (1)(V) is about 0.033 +/- 0.001, which indicates the secondary component is overluminous. Thus, this blue straggler likely results from a substantial mass exchange between these two components.