Our Galaxy is called the Milky Way. The 12 zodiacs are examples on such. Used to label all sorts of stuff in space, that now are known as star cluster or galaxies. It is sometimes still used for a concentration of gas and dust. These stars are produced when the hydrogen in the core of the star has fused into the more heavy helium.
Gravity forces the star to contract, but at the same time it heats up.
The hydrogen around the core now burns more fiercely and causes the outer envelope of the star to expand and thus cool. This low surface temperature produces light at longer wavelength. The atoms loose some of their electrons. It becomes a small hot White Dwarf. They are created when very massive stars explode, leaving this neutron 'ball' behind.