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

New near-ultraviolet and visible [O III] observations of SN 1987A obtained 2511 and 2533 days after outburst with the Corrective Optics Space Telescope Axial Replacement (COSTAR) corrected Faint Object Camera on board the Hubble Space Telescope are presented. Even though the supernova is now very faint (m congruent-to 19), the new data are of dramatically higher quality than those obtained previously with the aberrated telescope. The images-which are now no longer hampered by the spherical aberration halos of the two nearby companion stars-reveal a well-resolved symmetrical expanding envelope that can be traced out to a radius of congruent-to 275 mas or congruent-to 9400 km s-1 in the near-UV. The apparent diameter of the ejecta has grown to 255 +/- 2 mas (FWHM) in the near-UV and 167 +/- 5 mas (FWHM) in the visible, in close agreement with the expansion rates inferred from earlier FOC observations obtained on days 1275 and 1754. The improved angular resolution provided by the corrective optics also reveals that structure in the shape of an incomplete shell-like crescent has started to form within the inner congruent-to 60 mas core of the nebula.