Cepheid Radii from Infrared Photometry

Abstract We have determined radii for Cepheids using nearinfrared K(2.2 µm) photometry and Balona’s approach to the Baade-Wesselink method of radius determination. The lower sensitivity of the K flux to temperature variations results in improved sensitivity to radius changes. We present the results of maximum-likelihood radius solutions for Cepheids with modern radial velocity curves. We point out limitations of the Balona technique as it is currently applied in the optical and suggest improvements.