Here's why:

* Higher Core Temperatures: High-mass stars have much greater gravitational forces due to their larger mass. This leads to higher core temperatures, which are essential for nuclear fusion to occur.

* Higher Density: The denser core of a high-mass star also contributes to a higher fusion rate.

* Faster Fusion Reactions: The higher temperatures and densities in high-mass stars accelerate the rate of nuclear fusion reactions.

In contrast:

* Low-mass stars have lower core temperatures and densities. This results in slower fusion rates and longer main sequence lifetimes.

Key Takeaways:

* Fusion Rate: High-mass stars fuse hydrogen into helium at a much faster rate than low-mass stars.

* Main Sequence Lifetime: High-mass stars have shorter main sequence lifetimes because they burn through their fuel faster.

* Luminosity: High-mass stars are much more luminous than low-mass stars because they have higher fusion rates.

Let me know if you'd like more detail on any of these points!