Question

How do stars form? Are they hot or cold?

Answer 1

There are huge clouds of Gas and dust in space.It is called Nebula. Due to some shock waves the gases accumulate in one place and have more gravity than other areas of gas..

Explanation:

This process of gravitational accumulation continues and at the core pressure and temperature goes up. When temperature reaches about 15000000 degree K nuclear fusion stars and the star is born.
They are very hot. For example the Sun has a core temperature of about 15 million degrees and surface is about 5700 deg K![enter image source here]
picture britanica.com.