Supernovae are classified into two main types: Type I and Type II. Type I supernovae occur in binary star systems where one star is a white dwarf. When the white dwarf accumulates enough material from its companion star, it can trigger a runaway nuclear reaction, leading to a powerful explosion. Type II supernovae happen when massive stars, at least eight times the mass of the Sun, exhaust their nuclear fuel. This causes the core to collapse under gravity, resulting in a violent explosion. Both types play a crucial role in enriching the universe with heavy elements and influencing stellar evolution.