Instantaneous recycling approximation

Errors in the use of the instantaneous recycling approximation need to be considered, depending on the assumed history of star formation and mass ejection. After long times, e.g. 15 Gyr, low-mass stars eject relatively metal-poor material and modify the distribution in a similar way to what happens in some of the inflow models discussed below. However, it is still rather doubtful whether any Simple model can explain the abundance distribution function as well as satisfying other constraints. 

Properties of the 1-zone model were systematically studied by Talbot and Arnett (1971), who contrasted the instantaneous recycling approximation with an initial burst approximation which is the opposite extreme. In the latter case, most of the... 

Instantaneous recycling cannot be used to describe the formation of elements, such as iron, to which there is a significant contribution from stars that take a non-negligible time to complete their evolution. This case can still be handled within the framework of analytical models by a delayed production approximation (Pagel 1989a), which works by the simple device of assuming that the delayed element or component thereof starts to be released at a single time A after the onset of star... 

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