AAS 198th Meeting, June 2001
Session 42. Star Clusters
Display, Tuesday, June 5, 2001, 10:00am-6:30pm, Exhibit Hall

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[42.07] NGC 3201 Photometry Results: Differential Extinction Map, Color-Magnitude Diagram, and Variable Star Candidates

K. von Braun, M. Mateo (University of Michigan)

We present photometry results of our extensive monitoring project of the low-latitude Galactic globular cluster NGC 3201, one of approximately 15 globular clusters (GCs) we are probing for the existence of eclipsing binary systems. In order to obtain reliable photometry for the stars in the cluster, we created a differential reddening map to correct for the significant, variable extinction across the field of view. Our binary star detection analysis revealed 14 short-period variable stars in the field. 11 of these variable stars are eclipsing binaries, one is an RR Lyrae, and two are thus far unclassified systems. Among the eclipsing binary stars, nine are of the W Ursa Majoris type, one an Algol system, and one a detached system. Using spectroscopic follow-up observations, we conclude that only one variable star (a W UMa type blue straggler) is a member of NGC 3201.

We present the extinction map described above, along with the dereddened, deep-photometry color-magnitude diagram for NGC 3201, comprised of over 90 V and I images of the cluster. In addition, we show the phased lightcurves for all our variable star systems as well as their locations in the CMD and the field of view.

The author(s) of this abstract have provided an email address for comments about the abstract: kaspar@astro.lsa.umich.edu

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