The lifetime of a small star, like our Sun, is approximately 10 billion years.

Here's why:

* Smaller stars burn their fuel more slowly: They have less gravity, so their core pressure is lower. This means they fuse hydrogen into helium at a slower rate.

* Longer lifespan: Since they burn their fuel more slowly, they have a longer lifespan compared to larger, more massive stars.

Important Note: The exact lifespan of a small star can vary slightly depending on its mass. Smaller stars (red dwarfs) can have lifespans of trillions of years.