The effects of different Type Ia SN yields on Milky Way chemical evolution

Abstract

We study the effect of different Type Ia SN nucleosynthesis prescriptions on the Milky Way chemical evolution. To this aim, we run detailed one-infall and two-infall chemical evolution models, adopting a large compilation of yield sets corresponding to different white dwarf progenitors (near-Chandrasekar and sub-Chandrasekar) taken from the literature. We adopt a fixed delay time distribution function for Type Ia SNe , in order to avoid degeneracies in the analysis of the different nucleosynthesis channels. We also combine yields for different Type Ia SN progenitors in order to test the contribution to chemical evolution of different Type Ia SN channels. The results of the models are compared with recent LTE and NLTE observational data. We find that ”classical” W7 and WDD2 models produce Fe masses and [α/Fe] abundance patterns similar to more recent and physical near-Chandrasekar and sub-Chandrasekar models. For Fe-peak elements, we find that the results strongly depend either on the white dwarf explosion mechanism (deflagration-to-detonation, pure deflagration, double detonation) or on the initial white dwarf conditions (central density, explosion pattern). The comparison of chemical evolution model results with observations suggests that a combination of near-Chandrasekar and sub-Chandrasekar yields is necessary to reproduce the data of V, Cr, Mn and Ni, with different fractions depending on the adopted massive stars stellar yields. This comparison also suggests that NLTE and singly ionised abundances should be definitely preferred when dealing with most of Fe-peak elements at low metallicity.

A New Set of Chisels for Galactic Archeology: Sc, V, and Zn as Taggers of Accreted Globular Clusters*

“…Unlike Zn, whose nucleosynthesis in stars is pretty well understood (see previous paragraphs), the detailed nucleosynthetic paths leading to the stellar production of Sc and V still deserve investigation (see Cowan et al 2020;Kobayashi et al 2020 for recent reappraisals from the observational and theoretical point of view, respectively). Notably, different initial conditions of exploding white dwarfs leading to type Ia supernovae may result in very different V yields (e.g., Shen et al 2018;Leung & Nomoto 2020) with sizable consequences on the predictions of chemical evolution models (Palla 2021) that have yet to be fully explored. Our results clearly highlight the importance of Sc, V, and Zn as chemical taggers and will hopefully inspire further theoretical work.…”

Discovery of a Highly Neutronized Ejecta Clump in the Type Ia Supernova Remnant 3C 397

“…Nevertheless, explosions of near-M Ch WDs are still necessary from the perspective of the chemical evolution in the Milky Way (e.g., Seitenzahl et al 2013a;Kobayashi et al 2020;Palla 2021) and galaxy clusters (e.g., Mernier et al 2016;Hitomi Collaboration 2017), and even evolved dwarf spheroidal galaxies (de los Reyes et al 2020). This is because efficient production of neutron-rich isotopes of the Fe-peak elements, such as 54 Cr, 55 Mn, and 58 Ni, require electron capture processes that take place only in the dense core of near-M Ch SNe Ia (e.g., , and the contributions of sub-M Ch SNe Ia cannot account for the observed abundances of these species.…”

Two sequences in the age-metallicity relation as seen from [C/N] abundances in APOGEE

“…This could be attributed to a different metallicity effect for the progenitor (hence timescale) of the SNIe, affecting in a different way the [Ni/Fe] abundance ratios. It would be the difference of environments leading to different contributions form SNIa subclasses (Palla 2021). The slight increase at metallicities above solar has been seen in the literature (Adibekyan et al 2012;Bensby et al 2014) as well as when considering the bulk of the APOGEE data (Jönsson et al 2020).…”

“…Mn and Ni on the other hand are produced in SNIa, and given the variety of progenitors for SNIa, including the binary companion of the exploding white dwarfs, both elements have a dependency in metallicity (Kobayashi et al 2020b) but also in the explosion mechanism (Palla 2021). Manganese, while difficult to measure because of the strong hyperfine structure splitting in their lines, is one of the best suited elements to There are some possible explanations that can help understanding this difference.…”