# The Evolution of Dust Opacity in Core Collapse Supernovae and the Rapid Formation of Dust in Their Ejecta

## TL;DR

This paper suggests that dust in core collapse supernovae forms rapidly within two years, with most of the dust becoming observable only decades later as the ejecta's IR opacity decreases, challenging the idea of slow dust formation.

## Contribution

It introduces a new model proposing rapid dust formation in supernova ejecta, contrasting with previous interpretations of gradual dust accumulation over decades.

## Key findings

- Dust condenses within two years after explosion.
- Most dust remains hidden in early epochs due to IR opacity.
- Decades are needed for the entire dust content to become observable.

## Abstract

Infrared (IR) observations of core collapse supernovae (CCSNe) have been used to infer the mass of dust that has formed in their ejecta. A plot of inferred dust masses versus supernova (SN) ages shows a trend of increasing dust mass with time, spanning a few decades of observations. This trend has been interpreted as evidence for the slow and gradual formation of dust in CCSNe. Observationally, the trend exhibits a $ t^2$ behavior, exactly what is expected from an expanding optically thick ejecta. In this case, the observed dust resides in the infrared (IR)-thin "photosphere" of the ejecta, and constitutes only a fraction of the total dust mass. We therefore propose that dust formation proceeds very rapidly, condensing most available refractory elements within two years after the explosion. At early epochs, only a fraction of the dust emission escapes the ejecta accounting for the low observed dust mass. The ejecta's entire dust content is unveiled only a few decades after the explosion, with the gradual decrease in its IR opacity. Corroborating evidence for this picture includes the early depletions of refractory elements in the ejecta of SN1987A and the appearance of a silicate emission band around day 300 in SN~2004et.