A Near-infrared Variant of the Barnes-evans Method for Finding Cepheid Distances Calibrated with High-precision Angular Diameters

The advantages of a near-infrared variant of the Barnes-Evans method for estimating distances to Cepheid variables are described and quantiied. A surface brightness-color relation for K photometry and the (V ?K) 0 color index is established using modern , high-precision angular diameters from optical interferometers. Applied to data for the galactic (cluster) Cepheid U Sgr, this method yields a distance of 0.660 0.024 kpc and a true distance modulus of 9.10 0.07 mag. This estimate compares with the true distance modulus of 9.37 0.22 mag estimated by Gieren, Barnes, and Mooett (1993) using the classical Barnes-Evans technique. The possibility of estimating distances of LMC and SMC Cepheids directly { without intermediate steps { is discussed. The feasibility of determining the distance of M31 or M33 using this technique is examined and is probably within the reach of 8m-class telescopes.