35 day spectroscopic effects in HZ Herculis.

New spectroscopic data are presented of HZ Her, which have about 2 A-resolution, and cover both 1.7 day orbital and 35 day (precessional?) periods. Data include measures of principal absorption-line velocities and asymmetries, and emission-line velocities and intensities. Orbital parameters derived from Balmer and He I velocities are found to be modulated over half the 35 day period of the system. This can be generally understood in terms of a variable X-ray heating, modulated by a thick precessing disk about the secondary. Models for such a variable heating fit the principal effects and yield a primary star orbital velocity of 83 + or - 3 km/s. This implies masses of 1.91 and 0.93 solar mass for the two stars the emission-line features are found to vary in velocity with an amplitude of about 105 km/s and a phase shift of 0.3 with respect to the absorption, suggesting a principal origin above the trailing side of the heated face of the primary star. Line intensity variations are discussed and lend support to these conclusions.