Type II supernova spectra are poor in hydrogen because stars that explode this way use up all their hydrogen before they leave the main sequence.

Question

Quizplus · Accepted Answer

Type II supernovae result from the core collapse of massive stars that still have a significant amount of hydrogen in their outer envelopes. The presence of hydrogen lines in their spectra is actually a defining characteristic of Type II supernovae.

Type II Supernova Spectra Are Poor in Hydrogen Because Stars