H(alpha) variations of the RS CVn type binary ER Vulpeculae

Various dedicated satellite projects are underway or in advanced stages of planning to perform high-precision, long duration time series photometry of stars, with the purpose of using the frequencies of stellar oscillations to put new constraints on the internal structure of stars. It is known (cf. Brown et al. 1994) that the effectiveness of oscillation frequencies in constraining stellar model parameters is significantly higher if classical parameters such as effective temperature and luminosity are known with high precision. In order to optimize asteroseismic campaigns it is therefore useful to select targets from among candidates for which good spectroscopic and astrometric data already exists. This paper presents selection criteria, as well as redeterminations of stellar luminosity and reddening for stars satisfying these criteria.