Contraints on Be star geometry from combined photometric, IR excess, and optical polarimetry data

Abstract

Many atemps have alreadt been made to propose a global physical model for a Be star by compiling seperate tudies. Unfortunately; photometric studies are usually left out of these syntheses. We here combine four different kinds of observations (photometric periode, rotation velocity, instrinsic linear polarisation in the visual and IR excess) to see if they contain compatible information. From this study, we try to put constraints on the geometry on the stellar disc. We find that the IR colour excess is not correlated to the photometric variability, contrary to the polarisation. The latter shows equal correlations with v sin i and its square, indicating that the polarisation is an equally important function of sin i and sin² i. The relation between the photometric period and the polarisation indicates a possible link between stellar pulsation and mass loss. We stress, however, that our results are based on a very limited number of stars.