Population II

Population II objects are old, red stars and other objects found in the galactic halo and galactic bulge of a spiral galaxy, such as our own, near the galactic center, and in parts of the disk of the galaxy which are well away from the galactic plane. The halo contains individual old stars and large groupings known as globular clusters. Population II stars make up the overwhelming bulk of the stellar population in elliptical galaxies. Pop II stars follow highly elliptical orbits around the galactic center and are relatively deficient in heavy elements (i.e., those heavier than hydrogen or helium) because they formed when their parent galaxy was young, before much stellar nucleosynthesis had taken place. The importance of heavy elements in planet formation suggests that few, if any, Population II stars have worlds in orbit around them.