WHERE SUPERNOVA OCCUR?

Supernova are seen to occur in galaxies all over the Universe. Galaxies are basically classified into three major groups: spirals, elliptical  and irregulars. Now, Type II and Type Ibc supernova are seen to occur only in spiral and irregular galaxies, and these supernova also tend to be discovered in regions of these galaxies where star formation, particularly the formation of massive stars, most certainly has recently occurred in the last 10 million years or so. These supernova have not been seen in elliptical galaxies. It is therefore thought that these supernova arise from the explosions of massive stars in galaxies. Type Ia supernova are discovered in all three types of galaxies. But, Type Ia supernovae are generally not found near massive star formation. Since very little, if any, star formation occurs today in elliptical galaxies, it is thought that Type Ia supernova arise from older, less massive stars.

    The synthesis of the heavy elements is thought to occur in supernova, that being the only mechanism which presents itself to explain the observed abundances of heavy elements.

(Source: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/snovcn.html)