Distances to eclipsing binaries : an application of the Barnes-Evans relation

A novel method of estimating distances to all double-lined eclipsing binaries is presented. The method is based on the newly discovered Barnes-Evans relation, is completely free from any assumptions about spectral classification, luminosity class, or effective temperature, and is essentially independent of interstellar reddening for stars later than AO. The method is tested on those systems for which meaningful trigonometric parallaxes and V: R photometry are available, with the result that the new distance scale does not differ significantly from the trigonometric distance scale. The current accuracy is about +- 0.2 mag in absolute magnitude for well observed systems, but this should eventually be reduced to +- 0.1 mag as the B-E relation becomes better calibrated. The number of systems to which the method could be applied successfully with existing equipment is thought to be about 500. In this paper distances are derived to nine systems from existing V: R photometry.