What does an elliptical galaxy contain?

Generally speaking, elliptical galaxies are thought to have formed either from the monolithic collapse of primordial gas or through merging processes, but in any case, they are very old, with little hydrogen gas remaining to form stars; as a result, the majority of the stars in these galaxies are low-mass stars, as the young, massive stars would simply die out in a few billions of years, while the low-mass stars last for billions of years. The dust contents of individual galaxies vary.

It should be noted, though, that in certain instances, elliptical galaxies exhibit residual star formation or have star-forming outer regions; in such cases, rejuvenation remains likely provided gas replenishment takes place (in some way, such as through a merger with a gas-rich spiral).

Elliptical galaxies are characterized by a low abundance of interstellar gas and dust, a nearly spherical shape, and a high proportion of older stars with little to no star formation.