What characteristic defines a Type II supernova, distinguishing it from Type Ib or Ic?

Answer

The presence of a hydrogen envelope

Type II supernovae are those high-mass star explosions where the star retains its hydrogen envelope at the time of collapse, whereas Type Ib and Ic have lost their hydrogen and/or helium envelopes, often due to intense stellar winds.

What characteristic defines a Type II supernova, distinguishing it from Type Ib or Ic?
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