Abstract We present the results of VLBI observations at 5 GHz and 8.4 GHz of the compact symmetric object (CSO) OQ208. Images taken on four epochs at 5 GHz and one at 8.4 GHz show that the parsec radio structure of the source consists of two mini-lobes, both of them are resolved into two hot-spots. We note that the component D is stronger than the component C in the south-west region at 5 GHz, indicating that component D is less free-free absorbed than C at low frequency. On the basis of the separation of components A and D, a proper motion of 0.032±0.02 mas yr-1 between the two mini-lobes is estimated. This value is about half the previous estimates based on the separation of components A and C with 8.4 GHz VLBI data. The reason for the decrease in the expansion velocity is discussed.
Keywords galaxies: individual (Mkn 668, OQ208) --- galaxies: active
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