Rotation and the Cepheid Mass Discrepancy
  We recently showed that rotation significantly affects most observable Cepheid quantities, and that rotation, in combination with the evolutionary status of the star, can resolve the long-standing Cepheid mass discrepancy problem. We therefore provide a brief overview of our results regarding the problem of Cepheid masses. We also briefly mention the impact of rotation on the Cepheid period-luminosity(-color) relation, which is crucial for determining extragalactic distances, and thus for calibrating the Hubble constant. 
Richard I. Anderson, Sylvia Ekstr\"om, Cyril Georgy, Georges Meynet,   Nami Mowlavi, and Laurent Eyer
astro-ph.SR