Star life cycles, illustration - stock illustration

Life cycle of stars, illustration. All stars are born from the contraction of a large gas cloud into a spinning disc of gas and dust called a protoplanetary nebula. Red dwarfs, once they have left the main-sequence, continually contract and end their existences as white dwarfs. Low-mass stars such as the Sun expand into red giants when they run out of reactive elements, then lose their outer layers to form a planetary nebula, leaving behind a white dwarf, the core of the original star. Blue giants expand nto red supergiants, then explode as supernovae, leading to the formation of either a black hole or a neutron star