Searching for Open Cluster Variable Stars Using Short Duration Unfiltered Images (Abstract)

Volume 34 number 2 (2006)

Jeffrey A. Wilkerson

T. S. Brown

B. K. Lacoul

Abstract

(Abstract only) As part of an ongoing project to search for statistical evidence of isolated apparent flux transients in stars, such as might arise from occultation by Kuiper Belt Objects, we have acquired numerous unfiltered images from the fields containing several open star clusters. A typical data set for a single cluster consists of hundreds or thousands of images of a few seconds’ duration from each clear night in a two- to three-month observing window. We have begun assessing the viability of utilizing these data sets to search for variable stars in these fields. Variable stars in clusters are useful for understanding both stellar evolution and the dynamical evolution of regions of relatively high stellar density. Cluster populations can also prove useful in calibrating various distance estimation techniques. With so many images from a single night, our data are particularly sensitive to variable stars with periods less than a day (e.g., W UMa and δ Scuti stars). Because our data sets cover many nights over several months we can also reliably detect longer period eclipsing binary stars. We report our technique for identifying stellar variability given the residuals inherent in light curves constructed from unfiltered images. We have tested our technique on the fields containing M67 and NGC 129 and we report the results of those tests as well.