Galactic restrictions on iron production by various Types of supernovae

TL;DR

This paper introduces a statistical method to decompose the contributions of different supernova types to galactic iron production, accounting for spiral arm influences and progenitor star ages, providing new insights into iron synthesis sources.

Contribution

It develops a novel theory of oxygen and iron synthesis considering spiral arm effects and distinguishes contributions from supernovae Types II and Ia without prior assumptions.

Findings

Tardy supernovae Ia contribute about 35-50% of galactic iron.

Supernovae Types II and prompt Ia account for roughly 50-65% of iron.

The iron contribution varies with supernova explosion parameters and delay time distribution.

Abstract

We propose a statistical method for decomposition of contributions to iron production from various sources: supernovae Type II and the subpopulations of supernovae Type Ia -- prompt (their progenitors are short-lived stars of ages less then $\sim$100 Myr) and tardy (whose progenitors are long-lived stars of ages $>$100 Myr). To do that, we develop a theory of oxygen and iron synthesis which takes into account the influence of spiral arms on amount of the above elements synthesized by both the supernovae Type II and prompt supernovae Ia. We solve this task without of any preliminary suppositions about the ratio among the portions of iron synthesized by the above sources. The relative portion of iron synthesized by tardy supernovae Ia for the life-time of the Galaxy is $\sim$35 per cent (in the present ISM this portion is $\sim$50 per cent). Correspondingly, the total portion of iron supplied to the disc by supernovae Type II and prompt supernovae Ia is $\sim$65 per cent (in the present ISM this portion is $\sim$50 per cent). The above result slightly depends on the adopted mass of oxygen and iron synthesized during one explosion of supernovae and the shape (bimodal or smooth) of the so-called Delay Time Distribution function. The portions of iron mass distributed between the short-lived supernovae are usually as follows: depending on the ejected masses of oxygen or iron during one supernovae Type II event the relative portion of iron, supplied to the Galactic disc for its age, varies in the range 12 - 32 per cent (in the present ISM 9-25 per cent); the portion supplied by prompt supernovae Ia to the Galactic disc is 33 - 53 per cent (in ISM 26 - 42 per cent).