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.
@article{arxiv.1801.06463,
title = {Late formation of silicon carbide in type II supernovae},
author = {Nan Liu and Larry R. Nittler and Conel O'M. D. Alexander and Jianhua Wang},
journal= {arXiv preprint arXiv:1801.06463},
year = {2018}
}