A
Type II supernova (plural:
supernovae or
supernovas) results from the rapid collapse and violent explosion of a massive
star. A star must have at least 8 times, and no more than 40–50 times, the
mass of the Sun for this type of explosion. It is distinguished from other types of
supernovae by the presence of hydrogen in its
spectrum. Type II supernovae are mainly observed in the
spiral arms of
galaxies and in
H II regions, but not in
elliptical galaxies.