Two particular EA-type binaries in the globular cluster omega Centauri

Abstract

We analyzed the B and V light curves of two EA-type binaries V211 and NV358 using the WD code for the first time. Our analysis shows that V211 is a typical Algol-type binary and NV358 is a well detached binary system. As the two binaries are definite proper motion members of omega Centauri, we estimated their physical parameters, obtaining M_1=1.13\pm0.03M_\odot, R_1=0.98\pm0.01R_\odot and M_2=0.33\pm0.01M_\odot, R_2=0.92\pm0.01R_\odot for V211; M_1=1.30\pm0.05M_\odot, R_1=1.03\pm0.01R_\odot and M_2=0.58\pm0.02M_\odot, R_2=0.78\pm0.01R_\odot for NV358. On the color-magnitude diagram of omega Centauri, V211 is located in the faint blue straggler region and its primary component is more massive than a star at the main-sequence turnoff. Therefore, V211 is a blue straggler and should be formed by mass transfer from the secondary component to the primary. The age of NV358 is less than 1.93 Gyr, indicating that it is much younger than first-generation stars in omega Centauri. As NV364 in omega Centauri, NV358 should be a second-generation binary.

9 pages, 3 figures, accepted to Research in Astronomy and Astrophysics

References in corpus (9)

• The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851
• The radial distribution of blue straggler stars and the nature of their progenitors
• MCAO near-IR photometry of the Globular Cluster NGC 6388: MAD observations in crowded fields
• The surprising external upturn of the Blue Straggler radial distribution in M55
• The Gradients in the 47 Tuc Red Giant Branch Bump and Horizontal Branch are Consistent With a Centrally-Concentrated, Helium-Enriched Second Stellar Generation
• Search and analysis of blue straggler stars in open clusters
• The non-segregated population of blue straggler stars in the remote globular cluster Palomar 14
• The Clusters AgeS Experiment (CASE). II. The Eclipsing Blue Straggler OGLEGC-228 in the Globular Cluster 47 Tuc
• Modelling early-type stars in eclipsing binaries of open clusters: a new method for age determination from ratio of radii