This made detection of its remnant difficult — early attempts were unsuccessful. In 1988, R. A. Fesen and others used the 4-meter Mayall telescope at Kitt Peak to discover 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, which were likely created during the explosion. There is some evidence for spherical symmetry in the explosion; this would mean that this type Ia supernova was not triggered by merging. References External links Light curve on the Open Supernova Catalog Andromeda (constellation) Supernovae Andromeda Galaxy Andromedae, S 0182 18850817 Durchmusterung objects