How are Type II, Ib, or Ic supernovae classified?
Answer
By whether the star retained its outer hydrogen and helium layers before exploding.
The specific classification among Type II, Ib, or Ic depends on the remnants of the star's outer layers—specifically, whether the star still possessed its outer hydrogen and helium layers when the core-collapse explosion occurred.

Related Questions
What is the typical initial mass requirement for a single star to undergo a core-collapse supernova?What is the fate of a star like our Sun, considered a low-mass star in this context?What phenomenon is responsible for triggering a Type Ia supernova explosion?What is the approximate mass limit that a white dwarf must breach via accretion to trigger a Type Ia event?Which elements are scattered across space following a supernova explosion?How are Type II, Ib, or Ic supernovae classified?What physical process leads to the core-collapse supernova in high-mass stars?What is the significance of Type Ia supernovae for cosmology?What structure halts the inward implosion of a massive star's core just before a core-collapse supernova?What distinguishes the timescale required for setting up a Type Ia supernova versus a core-collapse supernova?What is the ultimate fate for stars born with masses significantly below the threshold required for core-collapse supernovae?