Classical Algol systems (invited review)

Progress in the study of Algol-type binaries is looked at both in the light of more general efforts at compilation and categorization, and also some specific new and important observational results.Results can be referred to the well known underlying model of the semi-detached configuration and Roche lobe overflow mechanism. Successes and limitations of this model will be considered.Arising from such comparisons lines of future research are suggested. Some outstanding issues concern: (i) the evolutionary condition of the mass accreting component, (ii) instabilities and related effects in various regions of the flow, (iii) systematic outflow, (iv) the relationship of classical Algols to other evolved binaries.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.