What dictates whether a star becomes a White Dwarf or undergoes a Supernova?

The star's initial mass relative to the Sun ($M_{\odot}$)

The fundamental factor determining a star's entire evolutionary pathway, including its ultimate remnant state, is its initial mass measured in solar masses ($M_{\odot}$). Stars whose masses are between $0.08$ and approximately $8 M_{\odot}$ follow a path where they cannot sustain fusion beyond helium, leading to the shedding of outer layers and stabilization as a white dwarf, which cools thermally. Conversely, stars beginning with substantially more mass, specifically greater than about eight times the mass of the Sun ($8 M_{\odot}$), possess sufficient gravitational power to fuse elements all the way up to iron. This iron core formation triggers an immediate collapse and a massive supernova explosion, resulting in either a neutron star or a black hole, depending on the mass remaining after the explosion.