Note on the evolution of the Cepheids

Abstract

The hypothesis that classical Cephelda are normal products of the evolution of B-type is examined and its consequences are compared to observations. Agreement is found a) for the number of B stars and Cephelda in galactic dusters and in the general field b) the distribution of Cephelds in associations. An estimate of the lifetime of Cephelda is given; the result is 2,5x10⁶ years. Finally the period-frequency distribution of the Cephelds is derived theoretically and compared to observations; the agreement 1b satisfactory for the longer periods. The paper will be published in full elsewhere.