INFRARED EXCESS IN RS CVN AND ALGOL TYPE BINARIES CIRCUMSTELLAR ENVELOPE AROUND ACTIVE BINARY STARS

the analysis of the spectral energy distribution in the optical, near infrared and iras bandpasses has shown that rs cvntype binaries have infrared excess that has been attributed to the presence of circumstellar matter shells. among the sources showing ir excess, the mass of their dust shells have been estimated to be larger for those sources that appear slightly more evolved. a tentative hypothesis is that the circumstellar material we are now seeing is the result of continuous mass loss episodes and hence is presumably linked to the timeintegrated past magnetic activity. we propose to perform multifilter photometry of a selected sample of rs cvn and algol.s binary systems with isophot in order to reconstruct their energy distribution from near to far ir spectral domains. the targets have been chosen among those for which long term multiwavelength monitoring (from xray to radio bands) has allowed us to establish the level of their behaviour and magnetic activity. the catania and torino groups have been involved in optical and uv studies of active binary systems for several decades and have gained substantial expertise in this field. we should like now to complement our active binary studies with the important information contained in the ir spectral domain. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]