Stars are located in the center of each star-system, and acts as a main source of lighting for the star system.
Right now, every star looks and acts the same. If you get within two sectors of a star, your ship will start to take 80 heat damage to the blocks facing the star. Shielding does not block heat damage. Heat damage is applied repeatly as long as you stay near. You can hide behind asteroids and randomly generated stations to avoid this damage, but those objects will rotate as they orbit the star.
The stars sector is hollow, and you can fly into and out of it. However the heat damage while in the stars sector jumps to 666 and is applied to all sides of the ship.
Asteroids, stations, pirates, and shops will spawn in the two sector radius around the star where heat damage is applied. Asteroids and stations are not affected by heat damage.
As of version 0.09374, a warning will be given when your ship is within this damage radius.
Turning on the bloom setting will provide extra visual effects for stars, such as sun-rays, and will make them look different as well.