What type of galaxy has mostly old stars, without a lot of star formation?

Elliptical galaxies, such as M87 (left), have very little gas and dust. Because gas and dust are found in the clouds that are the birthplaces of stars, we should expect to see very few young stars in elliptical galaxies. In fact, elliptical galaxies contain primarily old, red stars (also known as Population II stars).

Elliptical galaxies vary widely in size. Both the largest and the smallest known galaxies are elliptical. Very large elliptical galaxies can reach 300 million light years in diameter. Dwarf ellipticals, which are very common, may contain only 1/100,000th as many stars as the Milky Way!