Revisiting the Classics: On the Statistics of Dust Formation in Novae

TL;DR

This study statistically analyzes dust formation in 40 novae, revealing that 50-70% produce dust, with optical+IR photometry effectively identifying dust-forming novae and suggesting a link between gamma-ray detection and dust production.

Contribution

It provides the first comprehensive statistical assessment of dust formation in novae, highlighting the role of optical+IR photometry and gamma-ray detection in understanding dust production mechanisms.

Findings

50-70% of novae produce dust, higher than previous estimates.

Optical+IR color changes effectively distinguish dust-forming novae.

Gamma-ray detected novae are more likely to form dust.

Abstract

While nova eruptions produce some of the most common and dramatic dust formation episodes among astrophysical transients, the demographics of dust-forming novae remain poorly understood. Here, we present a statistical study of dust formation in 40 novae with high-quality optical/IR light curves, quantitatively distinguishing dust-forming from non-dust-forming novae while exploring the properties of the dust events. We find that 50-70% of novae produce dust, significantly higher than previous estimates. Dust-forming novae can be separated from those that do not show dust formation by using the largest redward ($V-K$) colour change from peak visible brightness; ($V-J$) or ($V-H$) offer useful but less sensitive constraints. This makes optical+IR photometry a powerful tool to quantify dust formation in novae. We find that novae detected in GeV $\gamma$-rays by \emph{Fermi}-LAT appear to form dust more often than novae not detected by \emph{Fermi}, implying a possible connection between $\gamma$-ray producing shocks and dust production. We also find that novae that evolve very quickly ($t_2 < 10$ days) are much less likely to form dust, in agreement with previous findings. We confirm a correlation between $t_2$ and the time of the onset of dust formation (which occurs $\sim$1 week--3 months after maximum light), but conclude that it is primarily an observational artifact driven by dust formation determining when a nova drops 2 mag below peak. The significant fraction of novae that form dust make them ideal laboratories in our Galactic backyard to tackle the puzzle of dust formation around explosive transients.