Galactic constraints on supernova progenitor models

Abstract

Aims. To estimate the mean masses of oxygen and iron ejected per each type of supernovae (SNe) event from observations of the elemental abundance patterns in the Galactic disk and constrain the relevant SNe progenitor models.

Methods. We undertake a statistical analysis of the radial abundance distributions in the Galactic disk within a theoretical framework for Galactic chemical evolution which incorporates the influence of spiral arms. This framework has been shown to recover the non-linear behaviour in radial gradients, the mean masses of oxygen and iron ejected during SNe explosions to be estimated, and constraints to be placed on SNe progenitor models.

Results. (i) The mean mass of oxygen ejected per core-collapse SNe (CC SNe) event (which are concentrated within spiral arms) is similar to 0.27 M-circle dot; (ii) the mean mass of iron ejected by tardy Type Ia SNe (SNeIa, whose progenitors are older/longer-lived stars with ages greater than or similar to 100 Myr and up to several Gyr, which do not concentrate within spiral arms) is similar to 0.58 M-circle dot; (iii) the upper mass of iron ejected by prompt SNeIa (SNe whose progenitors are younger/shorter-lived stars with ages less than or similar to 100 Myr, which are concentrated within spiral arms) is <= 0.23 M-circle dot per event; (iv) the corresponding mean mass of iron produced by CC SNe is <= 0.04 M-circle dot per event; (v) short-lived SNe (core-collapse or prompt SNeIa) supply similar to 85% of the Galactic disk's iron.

Conclusions. The inferred low mean mass of oxygen ejected per CC SNe event implies a low upper mass limit for the corresponding progenitors of similar to 23 M-circle dot, otherwise the Galactic disk would be overabundant in oxygen. This inference is the consequence of the non-linear dependence between the upper limit of the progenitor initial mass and the mean mass of oxygen ejected per CC SNe explosion. The low mean mass of iron ejected by prompt SNeIa, relative to the mass produced by tardy SNeIa (similar to 2.5 times lower), prejudices the idea that both sub-populations of SNeIa have the same physical nature. We suggest that, perhaps, prompt SNeIa are more akin to CC SNe, and discuss the implications of such a suggestion.