OBSERVATIONS OF SN-1987A WITH THE COSTAR-CORRECTED FAINT OBJECT CAMERA

New near-ultraviolet and visible [O III] observations of SN 1987A obta ined 2511 and 2533 days after outburst with the Corrective Optics Spac e Telescope Axial Replacement (COSTAR) corrected Faint Object Camera o n board the Hubble Space Telescope are presented. Even though the supe rnova is now very faint (m congruent-to 19), the new data are of drama tically higher quality than those obtained previously with the aberrat ed telescope. The images-which are now no longer hampered by the spher ical aberration halos of the two nearby companion stars-reveal a well- resolved symmetrical expanding envelope that can be traced out to a ra dius of congruent-to 275 mas or congruent-to 9400 km s-1 in the near-U V. The apparent diameter of the ejecta has grown to 255 +/- 2 mas (FWH M) in the near-UV and 167 +/- 5 mas (FWHM) in the visible, in close ag reement with the expansion rates inferred from earlier FOC observation s obtained on days 1275 and 1754. The improved angular resolution prov ided by the corrective optics also reveals that structure in the shape of an incomplete shell-like crescent has started to form within the i nner congruent-to 60 mas core of the nebula.