Question

why are less massive stars thought to age more slowly than more massive stars, even though less massive stars have much less fuel?

Answer 1

It is believed that a less massive star will age more slowly than a more massive star, despite the fact that massive stars have much more fuel. The reason that a more massive star will burn out quicker is because it takes a significant more amount of energy to keep the star burning due to the increased diameter of the star compared to the less massive star. A less massive star will use its fuel less quickly due to being smaller and having less mass to fuel.

The massive star burns its fuel at a greater rate than the less massive star.