Proceedings of the International Astronomical Union

Contributed Papers

Eclipsing Binaries: Tools for Calibrating the Extragalactic Distance Scale

Alceste Z. Bonanosa1

a1 Carnegie Institution of Washington, 5241 Broad Branch Road, Washington, DC 20015, USA email:


In the last decade, over 7000 eclipsing binaries have been discovered in the Local Group through various variability surveys. Measuring fundamental parameters of these eclipsing binaries has become feasible with 8 meter class telescopes, making it possible to use eclipsing binaries as distance indicators. Distances with eclipsing binaries provide an independent method for calibrating the extragalactic distance scale and thus determining the Hubble constant. This method has been used for determining distances to eclipsing binaries in the Magellanic Clouds and the Andromeda Galaxy and most recently to a detached eclipsing binary in the Triangulum Galaxy by the DIRECT Project. The increasing number of eclipsing binaries found by microlensing and variability surveys also provide a rich database for advancing our understanding of star formation and evolution.