Late formation of silicon carbide in type II supernovae

TL;DR

This study reveals that silicon carbide dust grains from supernovae form at least two years post-explosion, supporting models of delayed dust condensation and explaining ongoing dust buildup observed astronomically.

Contribution

It provides the first direct isotopic evidence for late formation of SiC grains in supernovae, confirming delayed dust condensation models.

Findings

SiC grains show 49Ti and 28Si excess correlation

Formation occurs at least two years after explosion

Supports delayed dust condensation in supernovae

Abstract

We have found that individual presolar silicon carbide (SiC) dust grains from supernovae show a positive correlation between 49Ti and 28Si excesses, which is attributed to the radioactive decay of the short-lived (t1/2=330 day) 49V to 49Ti in the inner highly 28Si-rich Si/S zone. The 49V-49Ti chronometer constrains that these supernova SiC dust grains formed at least two years after their parent stars exploded. This result supports recent dust condensation calculations that predict a delayed formation of carbonaceous and SiC grains in supernovae. The astronomical observation of continuous buildup of dust in supernovae over several years can, therefore, be interpreted as a growing addition of C-rich dust to the dust reservoir in supernovae.