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

Abstract

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

accepted for the Astronomical Journal

References in corpus (7)

• Standard Galactic Field RR Lyrae. I. Optical to Mid-infrared Phased Photometry
• Spectroscopic Comparison of Metal-Rich RRab Stars of the Galactic Field with Their Metal-Poor Counterparts
• Hydrogen Balmer Line Broadening in Solar and Stellar Flares
• The RRC Stars: Chemical Abundances and Envelope Kinematics
• Dynamical structure of the pulsating atmosphere of RR Lyr - I. A typical pulsation cycle
• The Axial Rotation and Variable Macroturbulence of RR Lyrae and Red Horizontal Branch Stars
• First observation of H$\alpha$ redshifted emission in RR Lyr

Cited by in corpus (1)

• The Active Chromospheres of Lithium-Rich Red Giant Stars