Reddenings of Cepheids using BVI photometry

Abstract
The reddening free locus (B–V), (V–I)KC is set up for Cepheids by piecing together the loci for individual Cepheids and then fixing the zero point from stars in clusters and associations whose reddenings are believed to be known. The locus, used in conjunction with reddening lines derived in this paper, is employed to obtain reddenings for about 60 Cepheids. A similar exercise is carried out for published photometry on the Johnson system. The derived reddenings are compared with those found by Pel using the Walraven five-color system and Parsons & Bell (1975) using the Lick six-color system. All the above-mentioned results are in good agreement. However, when compared with results obtained from spectral type B–V relationships the agreement is poor. By comparing with color excesses obtained from Cepheids in clusters, associations, and the Carina region, it is shown that the photometric excesses are more nearly correct.