Galaxy types. Artwork showing four of the more common types of galaxy. From top to bottom, these are: elliptical; lenticular; spiral and irregular. Elliptical galaxies are common, and contain mainly old stars. They also have relatively less gas and dust than the other types. Lenticular galaxies are disc-shaped, and lack a well- differentiated nucleus. Spiral galaxies, like our own Milky Way, tend to have a nucleus of older stars, and hot gas, dust and young stars making up the spiral arms. Irregular galaxies tend to be small, and are commonly found as companions of larger galaxies, as the Magellanic Clouds are to the Milky Way.