Spectral supernova type versus explosion mechanism

Spectral labels classify observed features rather than directly naming the energy source. Hydrogen-rich Type II events are associated with core collapse, but hydrogen-poor stripped-envelope Ib/c events can also be core collapse. Ordinary Type Ia events are thermonuclear white-dwarf explosions. Absence of hydrogen alone does not establish a thermonuclear mechanism, and light-curve standardization does not imply identical progenitors.