COLOR EXCESSES ON A UNIFORM SCALE FOR 328 CEPHEIDS

Color excesses, EB-v, have been derived ab initio for 301 classical Cepheids and 27 Population II Cepheids from more than 10,000 published observations in various photometric systems. The excesses are on the scale defined in a 1987 paper by Fernie. Comparison with the excesses of Cepheids in clusters and associations as listed by Feast and Walker shows small differences that are slightly period-dependent, and a listing of excesses on the cluster/association scale is also given for all Cepheids. Among the various photometric systems, best results are obtained with the Strömgren and BV(I)C systems. In these systems better results are obtained if color indices are magnitude-averaged rather than intensity-averaged over the pulsational cycle, e.g., 〈B - V〉m is to be preferred over (〈B〉i - 〈V〉i).