  We discuss high resolution VLT/UVES observations (FWHM ~ 6 km/s) from October
2002 (day ~5700 past explosion) of the shock interaction of SN 1987A and its
circumstellar ring. A nebular analysis of the narrow lines from the unshocked
gas indicates gas densities of (1.5-5.0)E3 cm-3 and temperatures of 6.5E3-2.4E4
K. This is consistent with the thermal widths of the lines. From the shocked
component we observe a large range of ionization stages from neutral lines to
[Fe XIV]. From a nebular analysis we find that the density in the low
ionization region is 4E6-1E7 cm-3. There is a clear difference in the high
velocity extension of the low ionization lines and that of lines from [Fe
X-XIV], with the latter extending up to ~ -390 km/s in the blue wing for [Fe
XIV], while the low ionization lines extend to typically ~ -260 km/s. For
H-alpha a faint extension up to ~ -450 km/s can be seen probably arising from a
small fraction of shocked high density clumps. We discuss these observations in
the context of radiative shock models, which are qualitatively consistent with
the observations. A fraction of the high ionization lines may originate in gas
which has yet not had time to cool down, explaining the difference in width
between the low and high ionization lines. The maximum shock velocities seen in
the optical lines are ~ 510 km/s. We expect the maximum width of especially the
low ionization lines to increase with time.
