Structure and kinematics of the interstellar medium in front of SN 1987A

High-resolution (10 km s(-1)) CN III echelle spectra, sampled every 13 " in a 6' x 6' region around SN 1987A were obtained on the CTIO 4 m telescope. The map shows a complicated velocity structure consistent with that reporte d previously for the interstellar medium (ISM). Three components, V-hel = 2 65, 277, and 285 km s(-1) were identified as N157C (or the R1170 complex: s ee an earlier paper of Xu, Crotts, & Kunkel). The radius of this large supe rbubble was found to expand at 10 km s(-1), with a lifetime of 6 x 10(6) yr and a total energy of 3 x 10(51) ergs determined from its radius and veloc ity according to superbubble theory. The V-hel = 235 km s(-1) component cor responds to the near side of the 600 pc giant superbubble reported earlier. This bubble is over 10(7) years old, and has blown out of the Large Magell anic Cloud disk. Two other components, V-hel = 255 and 245 km s(-1) are ide ntified as the inner major light echo ring (a double-shell structure) at ab out 130 pc in front of SN 1987A. There are also two high-velocity component s, 300 and 313 km s(-1), which are possibly the far side of a superbubble i n which SN 1987A exploded. We also noticed that there are two components, a t 279 and 301 km s(-1) within 20 " of SN 1987A. These structures are probab ly due to the emission from the progenitor star's red supergiant wind. We f ind that the time it took the SN 1987A progenitor to move to the current lo cation 300 pc behind N157C is comparable to the age of N157C as well as tha t of the progenitor itself.