The compact core-jet region of the superluminal quasar 3C 216

Space very long baseline interferometry (VLBI) observations of the quasar 3 C 216 with the VLBI Space Observatory Programme (VSOP) reveal that the pars ec scale structure of the source can be well described by compact jet model s developed for interpreting the core region of radio-loud active galactic nuclei (AGN). The measured brightness temperature of T-B = 7.9 X 10(11) K i s comparable to the inverse Compton limit, from which we determine a lower limit of delta similar to 3 for the Doppler-boosting factor. The apparent t ransverse velocity of the superluminal component is beta (app) = (3.0 +/- 0 .2) h(-1), assuming a constant velocity, but deceleration of the jet materi al cannot be excluded from our data. A combination of the above values indi cates that the viewing angle of the core-jet to the line-of-sight is less t han 19 degrees, and the jet Lorentz-factor exceeds 2.4. The observed small size of the source is probably caused by both an interaction with the inter stellar medium and a projection effect.