Origin of Dust around V1309 Sco

TL;DR

This paper investigates the origin of dust around V1309 Sco, proposing that binary-merger ejecta efficiently produce dust, supporting the idea that common-envelope ejecta are significant cosmic dust sources.

Contribution

It demonstrates that dust around V1309 Sco is formed in binary-merger ejecta, highlighting the role of common-envelope ejecta in cosmic dust production.

Findings

Approximately 5.2×10⁻⁴ solar masses of dust are produced.

Dust grains are mainly silicate and iron, with radii around 10⁻⁵ cm.

Binary-merger ejecta's contribution to overall interstellar dust is negligible.

Abstract

The origin of dust grains in the interstellar medium is still open problem. \cite{Nicholls2013} found the presence of a significant amount of dust around V1309 Sco which maybe originate from the merger of a contact binary. We investigate the origin of dust around V1309 Sco, and suggest that these dust grains are efficiently produced in the binary-merger ejecta. By means of \emph{AGBDUST} code, we estimate that $\sim 5.2\times10^{-4} M_\odot$ of dust grains are produced, and their radii are $\sim 10^{-5}$ cm. These dust grains mainly are composed of silicate and iron grains. Because the mass of the binary-merger ejecta is very small, the contribution of dust produced by binary-merger ejecta to the overall dust production in the interstellar medium is negligible. However, it is the most important that the discovery of a significant amount of dust around V1309 Sco offers a direct support for the idea---common-envelope ejecta provides an ideal environment for dust formation and growth. Therefore, we confirm that common-envelope ejecta can be important source of cosmic dust.