Here's a breakdown:

* Orbital Period: The time it takes for a planet to complete one full orbit around its star is called its orbital period.

* Distance from the Star: The farther a planet is from its star, the longer its orbital path and the longer its orbital period, hence a longer year.

* Star's Mass: The mass of the star also plays a role, with more massive stars having a stronger gravitational pull, potentially causing planets to orbit faster and have shorter years.

* Other Factors: Although less significant, other factors like the presence of other planets in the system can also influence a planet's orbital period to a small extent.

In simpler terms: Think of a planet's year as the time it takes for that planet to go around its sun once. The further the planet is from its sun, the longer it takes to go around, and the longer its year.