The infrared variability and nature of symbolic stars- II. RR Tel.

The presence of a cool Mira-like component having a period of 387 days is established for the very slow nova symbiotic system RR Tel in the 1972-1981 period, using JHKL IR photometry. Single star models for the system are suggested to be unlikely in view of evidence for a similar periodicity in the photographic region prior to the 1944 outburst. These results are consistent with the presence of a constant period and mean luminosity Mira at all times. If the Mira component is normal, then the IR excess increases toward Mira minimum and may be interpreted as a partial heating of the dust by the blue component and/or ionized gas in the system. The evidence indicates that all slow novae contain cool giant or supergiant components, so that the systems must be of great physical size.