EXPANSION OF THE SUPERNOVA REMNANT RCW-103

A new CCD image of the supernova remnant RCW 103 was taken in 1995 to compare with a photographic plate taken in 1970. We calculated the pro per-motion expansion of the outer edge and several filaments by compar ing radial slices through each of the datasets. The mean expansion rat e of the outer edge is 1.'' 8 +/- 0.'' 2 per 25 years, or about 1100 k m s(-1). At this velocity the remnant is most likely around 2000 years old. In addition, it must have made the transition from the double-sh ock phase of evolution to the point-blast phase fairly recently for th e initial energy of the supernova explosion to be within a reasonable range.