Chemical Evolution of Spheroidal Systems(Proceedings of Japan-France Seminar on Chemical Evolution of Galaxies with Active Star Formation)

A model of chemical evolution for spheroidal systems is constructed assuming a relation between binding energy and mass of a system Ω_G∝M_G^ and a universal IMF of stars dn/dlogm∝m. Taking into account the effect of stopping the star formation due to gas removal by a galactic wind, we successfully reproduced the chemical and structural properties of gE galaxies, dE galaxies, and globular clusters. The average metallicity of stars in a system declines from gEs through dEs monotonically, while the galactic mass loss expands dEs most significantly among others, causing the distinct sequences of gEs, dEs, and globulars in the diameter-surface brightness diagram. It is suggested that all the spheroidal systems were formed as a one-parameter family of mass