Types of Stars
Each of the stars in the practically limitless universe is “born” in much the same way; gaseous elements of hydrogen and other elements become heated and pressurized until thermonuclear fusion begins. If this occurs near the remnants of a supernova explosion, a star field is formed, giving rise to a cluster of new stars.
These types of stars form so close to each other that they become gravitationally bound. Two, three, or four stars could be in orbit around each other, at such a distance that they appear to us on earth as a single point of light. About half of the stars within the known universe are multiple star systems.
In contrast, other stars are light years away from each other and spend most of their lives in a stable “main sequence” phase, often accompanied by planets, moons, and icy comets. They steadily burn hydrogen within their core until it’s depleted, and then, depending on the star’s temperature and size, they slowly evolve into a giant or super-giant.
