Final answer:
Our Sun will not experience a nova or white dwarf supernova because it lacks sufficient mass and is not part of a binary system where mass transfer could push a white dwarf over the Chandrasekhar limit. The Sun will eventually become a white dwarf and cool over time.
Step-by-step explanation:
The reason our Sun will never undergo a nova or a white dwarf supernova event is that its mass is not sufficient to reach these endpoints. Novae and white dwarf supernova events (also known as Type Ia supernovae) occur in binary star systems, where a white dwarf accumulates mass from a companion star. If the mass of the white dwarf approaches the Chandrasekhar limit, which exceeds 1.4 times the mass of the Sun (Msun), it can no longer support itself and begins to collapse, leading to an explosive event. However, our Sun is a solitary star, not part of a close binary system where mass transfer can take place, and it does not have the mass required to become a white dwarf that exceeds the Chandrasekhar limit.
At the end of its life cycle, the Sun will become a white dwarf after passing through the red giant phase, but it will lack the necessary conditions to turn into a nova or explode as a white dwarf supernova. Instead, the Sun's white dwarf will cool over time, eventually transforming into a black dwarf.