Search for OVI emission from the shocked circumstellar ring of SN 1987A

A search for O VI 1032-38 angstrom emission from the circumstellar shock interaction zones of SN 1987A was made with the FUSE satellite. The shock interaction of supernova ejecta with the dense inner ring began in the mid-1990s. Broad (FWHM similar to 300 km s(-1)) emission from optical coronal lines (e.g. [Fe X], [Fe XI], and [Fe XIV]) has emerged and increased exponentially in strength. O VI emission is expected to track the coronal lines and is expected to be the primary cooling transition for the million-degree shocked gas. In the most recent FUSE observation of SN 1987A, June 2004, a weak broad O VI feature may be present. An upper limit on the intrinsic O VI flux is similar to 1 x 10(-13) erg cm(-2) s(-1) (corrected for foreground Galactic and LMC extinction). A follow-up observation of planned for mid-2007.