It eventually consumes the hydrogen in the core, and the star changes its structure by swelling into a red giant. Stars similar to the sun consume their hydrogen in about 10 billion years, but more massive stars will use up their supply in as little time as 10 million years. When a star runs out of fuel, it is near the end of its life. Sun-like stars will die slowly and quietly, turning into a white dwarf. Larger stars, however, explode and form a neutron star or a black hole.
Stellar explosions mean the death of one star, but can also mean the birth of a new one.
The size of stars varies between very large supergiants to tiny neutron stars that can have diameters as small as 10 miles. Our sun, with a diameter of 865,000 miles, is a medium size star. For the purposes of this webpage, we will consider low mass stars 3 solar masses or smaller. High mass stars will be larger than 3 solar masses.