Irregular nebular variables and neutrino emission

The suggestion that the less massive star will reach the Main Sequence stage earlier than the massive star due to the effect of neutrino emission according to the photon-neutrino coupling theory is supported by the observed behaviour of H-R diagram of irregular nebular variables. After reaching the Main Sequence stage the star should pulsate with a period due to the effect of neutrino emission which may be a possible explanation of other properties of irregular nebular variables.