Abstract:
Evolutionary discussion shows that the possibility of AR Lac being in a semi-detached state of evolution cannot be ruled out. The period variations of AR Lac have been analysed using Biermann & Hall's (1973) model for a system undergoing mass transfer. The yearly rates of period change and mass transfer are found to be respectively 1.7x10¯⁶ d and 6.2x10¯⁷M☉.
