Reddenings of Cepheids using BVI photometry

The reddening free locus (B-V), (V-I)sub(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 conjuction 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 other workers using the Walraven five-colour system and the Lick six-colour 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 colour excesses obtained from Cepheids in clusters, associations and in the Carina region it is shown that the photometric excesses are more nearly correct. (author)