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I. Liska (CUA)
Approximate analytic expressions for the time variation of the mass of stars and of gas, and the abundance of heavy elements in a galaxy are derived by applying the method of perturbation to the fundamental equations of the simple one-zone model. These equations are formulated in terms of coefficients which represent the processes governing the rate of change of gas mass and chemical abundances. In a closed system of constant mass these processes are all related to the stellar life cycle; gas is depleted from the interstellar medium (ISM) at the stellar birth rate and returned to the ISM in a chemically enriched form at the rate at which stars across the mass spectrum reach the end of their main sequence lives and eject much of their initial mass. Analytic formulations of these processes are calculated for two illustrative cases by an application of the classical perturbation technique to an initial no-gas-recycling approximation of the gas consumption rate. Specifically, expressions are derived in the case of a single initial burst of star formation and in the case of a constant star formation rate over some characteristic timescale.
The author(s) of this abstract have provided an email address for comments about the abstract: liska29@phys23.phys.cua.edu