Distances and Radii of Classical Cepheids

Abstract

We have used new BVRI photometry and radial velocities of a selection of bright classical Cepheids to determine their distances and radii through the surface brightness method. The improved photometry permitted, through the visual surface brightness relation, high-quality angular-diameter values for each Cepheid throughout its pulsation. The simultaneous radial velocities permitted the linear displacement curve to be phase-locked to the angular diameter variation. The results are individual distances and radii with considerably smaller uncertainty than could be obtained previously.