AAS 205th Meeting, 9-13 January 2005
Session 22 Open Clusters Young and Old
Poster, Monday, January 10, 2005, 9:20am-6:30pm, Exhibit Hall

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[22.12] The Search for Variable Stars in the Open Cluster M11

J. R. Hargis (Eastern University), E. L. Sandquist (San Diego State University), D. H. Bradstreet (Eastern University)

We present the first large-scale variability survey of the intermediate age (app. 200 Myr) open cluster M11 (NGC 6705, C 1848-063). Nearly 9,000 stars were observed for 16 nights (over two observing seasons) using the 1 m telescope at the Mount Laguna Observatory. Analysis was peformed using ensemble techniques resulting in high relative precision photometry. In total, 38 previously undetected variable stars were discovered and can be characterized as follows: 1 irregular (probably pulsating) variable, 6 delta Scuti variables, 13 detached eclipsing binary systems, 17 W UMa variables, and 1 unidentified variable. Two additional objects show evidence of variability and are likely detached eclipsing binary systems. Previous proper motion studies of M11 allow for membership determination for the bright stars, while the significant population of field stars significantly hampers membership determination for the fainter variable stars. Several variables have been identified as important for follow-up studies.

The author(s) of this abstract have provided an email address for comments about the abstract: jhargis@eastern.edu

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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.