Here's why:

* Pollux is a giant star: Pollux is a K-type giant star, meaning it is much larger and more luminous than our Sun.

* White dwarfs are remnants of stars: White dwarfs are the dense, hot remnants of stars that have exhausted their nuclear fuel. They are much smaller than giant stars.

Pollux is still actively fusing hydrogen in its core, while a white dwarf has already reached the end of its life cycle.