Hydrogen and Helium Shock Phenomena during Rising Light in RR Lyrae Fundamental Mode Pulsators

We present measurements of H and He emission absorption lines produced in RRab fundamental mode pulsators during primary light rise. The define universal progressions rise decay metal-poor stars. Such a progression cannot be constructed for metal-rich (those with [Fe/H]> -0.8) because weak I is detected only two the six our survey. Great variety exists phase variations blue- red-shifted components 5876 A line pre- post-emission phases. Detection measurable II 4686 eight RRab, three them Blazhko variables, provides an additional constraint on ionization Helium.