CIRCUMSTELLAR MATTER IN DIRECT IMPACT ALGOL SYSTEMS

Full-orbit H alpha observations have been analyzed to determine the tw o-dimensional distribution of the circumstellar gas in the four short- period Algols, U Sge, U CrB, RS Vul, and SW Cyg. In these systems, the gas stream resulting from Roche-lobe overflow directly impacts the ma ss-gaining star and feeds material into a structure known as a 'transi ent accretion disk'. The accretion regions observed in these systems i nclude a transient accretion disk that at least partially surrounds th e mass gainer, the gas stream, and possibly a chromospheric component associated with the magnetically active cool star.