Unravelling the infrared transient VVV-WIT-06: the case for an origin in a classical nova

TL;DR

This study analyzes the infrared transient VVV-WIT-06 and concludes that its properties are best explained by a classical nova outburst, based on lightcurve and spectral data.

Contribution

The paper provides the first convincing evidence that VVV-WIT-06 is a classical nova, with detailed estimates of its magnitude, distance, and extinction.

Findings

VVV-WIT-06 is best explained as a classical nova.

Estimated absolute K band magnitude at maximum was -8.2.

Distance to the object is approximately 13.35 kpc.

Abstract

The enigmatic near-infrared transient VVV-WIT-06 underwent a large amplitude eruption of unclear origin in July 2013. Based on its lightcurve properties and late-time post-outburst spectra various possibilities have been proposed in the literature for the origin of the object viz. a Type I supernova, a classical nova (CN) and a violent stellar merger event. We show that out of these possibilities, an origin in a CN outburst convincingly explains the observed properties of VVV-WIT-06. We estimate that the absolute K band magnitude of the nova at maximum was M$_K$ = -8.2 $\pm$ 0.5, its distance d = 13.35 $\pm$ 2.18 kpc and the extinction A$_V$ = 15.0 $\pm$ 0.55 magnitudes.