Revisiting the formation of molecules and dust in core collapse supernovae

Abstract

Context. Core-collapse Supernovae of Type II contribute the chemical enrichment of galaxies through explosion. Their role as dust producers in the high-redshift Universe may be of paramount importance. However, the type and amount of dust they synthesise after outburst is still a matter of debate and the formation processes remain unclear. Aims. We aim to identify and understand the chemical processes at play in the dust formation scenario, and derive mass yields for molecules and dust clusters at late post-explosion time. Methods. We revisit existing models by improving on the physics and chemistry of the supernova ejecta. We identify and consider new chemical species and pathways underpinning the formation of dust clusters, and apply a unique exhaustive chemical network to the entire ejecta of a Supernova with a 15 Msun progenitor. We test this new chemistry for various gas conditions in the ejecta, and derive mass yields for molecules and dust clusters. Results. We obtain the molecular component of the ejecta up to 11 years after explosion. The most abundant species are, in order of decreasing masses, O2, CO, SiS, SiO, CO2, SO2, CaS, N2, and CS. We identify molecules that are tracers of high-density clumps. As for dust clusters, we find the composition is dominated by silicates and silica, along with carbon dust, but with modest amounts of alumina. Pure metal clusters and metal sulphide and oxide clusters have negligible masses. High-density gas favours the formation of carbon clusters in the outer ejecta region whereas low temperatures hamper the formation of silicates in the oxygen core. The results are in good agreement with existing astronomical data and recent observations with the James Webb Space Telescope. They highlight the importance of chemistry for the derivation of dust budget from Supernovae.