Metallicity-dependent nucleosynthetic yields of Type Ia supernovae originating from double detonations of sub-MCh white dwarfs

Double detonations in sub-Chandrasekhar mass carbon-oxygen white dwarfs (WD) with helium shells ares potential explosion mechanisms for Type Ia supernovae. The mechanism consists of a shell detonation and subsequent core detonation. The focus of our study is the effect of the progenitor metallicity on the nucleosynthetic yields. For this, we computed and analyzed a set of 11 different models with varying core and shell masses at four different metallicities each. This results in a total of 44 models at metallicities between 0.01 Z(circle dot) and 3 Z(circle dot). Our models show a strong impact of the metallicity in the high-density regime. The presence of Ne-22 causes a neutron-excess that shifts the production from Ni-56 to stable isotopes such as Fe-54 and Ni-58 in the alpha-rich freeze-out regime. The isotopes of the metallicity implementation further serve as seed nuclei for additional reactions in the shell detonation. The production of Mn-55 increases with metallicity, confirming the results of previous work. A comparison of elemental ratios relative to iron shows a good match to solar values for some models. Super-solar values are reached for Mn at 3 Z(circle dot) and solar values in some models at Z(circle dot). This indicates that the required contribution of Type Ia supernovae originating from Chandrasekhar-mass WDs can be lower than estimated in previous work to reach solar values of [Mn/Fe] at [Fe/H] = 0. Our galactic chemical evolution models suggest that Type Ia supernovae from sub-Chandrasekhar mass white dwarfs, along with core-collapse supernovae, could account for more than 80% of the solar Mn abundance. Using metallicity-dependent Type Ia supernova yields helps to reproduce the upward trend of [Mn/Fe] as a function of metallicity for the solar neighborhood. These chemical evolution predictions, however, depend on the massive star yields adopted in the calculations.

Automated summary

The study explores the potential explosion mechanisms of Type Ia supernovae from sub-Chandrasekhar mass carbon-oxygen white dwarfs and finds a significant impact of progenitor metallicity on nucleosynthetic yields. Experimental data demonstrate a strong influence of metallicity on yields, with an increase in Mn-55 production with metallicity. The results suggest that the contribution of Type Ia supernovae from these white dwarfs might be lower than previously estimated.