A Search for Short-Term RV Variations in Early-Type Binaries

Abstract

We developed a procedure to disentangle the different radial velocity variations due to orbital motion, rotation, and pulsation based on an iterative mutual subtraction of orbital and short-term contributions. The method was successfully tested on a data set of over 2200 spectra of the eclipsing β Cep star EN Lac spanning a time interval of about 90 years. We further applied the procedure to early type binaries. For the A1 III star 21 Her we found short-term variations which indicate the presence of rotationally split nonradial pulsation (NRP) modes.