the supernova and thus substantial debris was/is from the relatively bright nucleus of the galaxy. this made detection of the supernova remnant difficult — early attempts were unsuccessful. in 1988, r. a. fesen and others using the 4-meter mayall telescope at kitt peak discovered the iron-rich remnant of the explosion. further observations were made with the hubble space telescope in 1999. the spectrum of the remnant shows the presence of iron, calcium and manganese, and they were likely created during the explosion. there is some evidence also for a spherical symmetry in the explosion; this would mean that this type ia supernova was not triggered by merging.