The Formation of Supernova Remnant 1987A

International audienceThe collision between the ejecta of SN 1987A and its circumstellar ring is underway. Now and in the next few years, we are watching radical changes in the circumstellar nebula as it is overrun by ejecta expanding at a substantial fraction of c, giving birth to a supernova remnant. We have already discovered (and published) previously, by virtue of this observational program, new interactions between the nebula and ejecta, in the form of ``hot spots'' appearing at the rate of 3 to 5 per year, and we now see the whole inner surface beginning to interact. The collision is predicted (and has been observed) to produce intense IR and optical emission, in new and previously observed lines. Depending on whether they arise in the ejecta or nebula, and whether they are shock or EUV excited, these lines have widths from ~ 10 to 15,000 km s^-1. Frequent moderate-dispersion spectra are needed to monitor these features. With the demise of HST/STIS, these spectra are especially crucial. Furthermore, spectra obtained with MIKE or Echelle are equally crucial. Given the relative unavailabilty of MIKE, we urge that Echelle be continued. All of these efforts, treating velocity scales, wavelengths and time intervals not covered by HST, will study for the first time ever the creation of a nearby supernova remnant