An optical--mid-infrared color evolution tool for nova identification using WISE data

TL;DR

This paper introduces a new infrared-based method using WISE data to identify and analyze novae, validating models of their evolution and estimating the Galactic nova rate.

Contribution

The study develops a pipeline utilizing infrared color criteria for nova identification and proposes a model for their color evolution, validated with WISE data.

Findings

Identified 41 optically confirmed novae in WISE catalog.

Established a strong correlation between optical and infrared color differences.

Estimated the Galactic nova rate at 40-50 per year.

Abstract

We present a novel approach for characterizing nova candidates by exploiting the infrared capabilities of the Wide-field Infrared Survey Explorer (WISE) catalog. We developed a pipeline to identify novae based on well-defined infrared criteria, and leveraging this pipeline, we successfully identified 41 optically confirmed novae in the WISE catalog. In particular, we focus on the color difference between the optical V band and the WISE 3.4 microns W1 band as a diagnostic. We compared their infrared light curves with their optical counterparts. We identified a strong correlation from which we proposed a color difference model that can be used for further identification and characterization of novae. Our analysis validates the mass-loss timescale theory, which predicts that systems with lower accretion rates accumulate larger envelopes and produce more massive ejecta. We also confirm models' prediction that the early color evolution of novae is governed by ejecta expansion and cooling. From our sample statistics, we infer a Galactic nova rate of approximately 40 to 50 novae per year, consistent with modern and infrared-corrected estimates. The resultant model from this work paves the way for future large-scale investigations of nova candidates.