Here's why:

* Nuclear Fusion: Stars are powered by nuclear fusion, a process where atoms fuse together, releasing immense amounts of energy in the form of heat and light.

* Temperature: The temperature at the core of a star is incredibly high, reaching millions of degrees Celsius. This heat is what makes them shine so brightly.

* Sun is a Star: Our Sun is just one star among billions in the Milky Way galaxy. All stars generate heat through nuclear fusion, making them hot objects.

However, different stars have different temperatures:

* Size and Mass: Larger, more massive stars are generally hotter than smaller, less massive stars.

* Color: The color of a star indicates its temperature. Blue stars are the hottest, followed by white, yellow, orange, and red stars, which are the coolest.

So, while all stars are hot, their temperature varies depending on their size, mass, and age.