Triple Mode Cepheid Masses

摘要

Cepheid wind enrichment from the surface and the instability mixing below the convection zones compete to give much deeper large Y homogeneous and transition layers than previously thought. The theoretical model data and derived masses are presented. It is shown that if the helium enrichment goes to 250,000 K (l-q = 2 x 10 exp -4 ) with a transition zone to 300,000 K (1-q = 5 x 10 exp -4 ) for AC And, its periods can be explained. For TU Cas a very unlikely model is required to give the three periods reported previously. 28 references. (ERA citation 04:004557)