Type I : Formed from the complete destruction of a White Dwarf (usually pushed over
the Chandrasekhar Limit by its evolving Binary Companion).
Comes from stars that had been of relatively low mass. Thus, Type I's trace an
OLD population.
A stellar Remnant is DESTROYED in this process.
The amount of light given off is very predictable, because it is always the same
amount of mass that is being destroyed, i.e.: 1.4 M suns. (we will find that they
make excellent "standard candles")
It releases lots of heavy elements (C, N, Fe, etc) into the interstellar medium,
thereby changing the chemical composition of the Galaxy.
Type II : Formed from the core collapse at the end of a star's evolution, when it
runs out of fuel.
Comes from stars that had been of relatively high mass. Thus, Type II's trace a
very young population (of massive stars).
A stellar Remnant (neutron star or black hole) is CREATED in this process.
The amount of light given off can vary by a lot. This is because the mass of the
final core going Supernova is never quite the same, and even if it did, not all of it is
entirely destroyed (though it might be). Instead, some of the mass is left in the form
of a neutron star or black hole.
It releases lots of heavy elements (C, N, Fe, etc) into the interstellar medium,
thereby changing the chemical composition of the Galaxy.