A multi-frequency study of symbiotic stars - III. Simultaneous ultraviolet and optical observations of AX Persei.

The results of UV and optical monitoring of the classical symbiotic star AX Per are reported. The recent visual postoutburst light curve is used to estimate the size of the binary components in the AX Per system and to speculate on the cause of unusual ingress/egress profiles. A similar analysis using a phase plot of He II intensity is used to determine the extent of the region responsible for the He II emission. These estimates offer no evidence that AX Per is a semidetached binary system. The depth of the observed postoutburst minima during eclipse casts doubt on previous estimates of the spectral type and class of the giant in the system and suggests that the source of optical continuum is smaller in outburst than in quiescence.