the stars making up globular clusters, the bulges and halos of spiral galaxies, and all elliptical galaxies: characterised by great age (star formation ceased 109 y ago), so that there are no blue supergiants or upper main sequence stars and the brightest stars are red giants; generally thought of as being low in heavy elements, but strictly this is true only of the halo, not of the bulge nor of large elliptical galaxies.