* Temperature and Color: The color of a star is directly related to its surface temperature. Blue stars are much hotter than yellow stars.

* "Hottest" is Relative: There are stars much hotter than blue stars, but they are classified as white or even blue-white.

Therefore, a blue star is hotter than a yellow star.

Here's a simplified breakdown:

* Blue Stars: Very hot (25,000 - 50,000 Kelvin)

* Yellow Stars: Medium temperature (5,000 - 10,000 Kelvin)

* Red Stars: Coolest (3,000 - 4,000 Kelvin)

Let me know if you'd like to know more about stellar classification!