A planetary nebula around nova V458 Vul undergoing flash ionization

TL;DR

This paper reports the discovery of a planetary nebula around nova V458 Vul, which was flash-ionized by the nova event, providing insights into the system's distance, age, and potential to produce a Type Ia supernova.

Contribution

It presents the first evidence of a planetary nebula associated with a nova, derived distance estimates, and discusses the system's evolutionary implications.

Findings

Distance of 13 kpc based on light travel time

Nebula is a ~14,000-year-old planetary nebula

System may produce a Type Ia supernova upon merging

Abstract

Nova V458 Vul erupted on 2007 August 8th and reached a visual magnitude of 8.1 a few days later. H$\alpha$ images obtained six weeks before the outburst as part of the IPHAS galactic plane survey reveal an 18th magnitude progenitor surrounded by an extended nebula. Subsequent images and spectroscopy of the nebula reveal an inner nebular knot increasing rapidly in brightness due to flash ionization by the nova event. We derive a distance of 13 kpc based on light travel time considerations, which is supported by two other distance estimation methods. The nebula has an ionized mass of 0.2 M$_{\odot}$ and a low expansion velocity: this rules it out as ejecta from a previous nova eruption, and is consistent with it being a ~14,000 year old planetary nebula, probably the product of a prior common envelope (CE) phase of evolution of the binary system. The large derived distance means that the mass of the erupting WD component of the binary is high. We identify two possible evolutionary scenarios, in at least one of which the system is massive enough to produce a Type Ia supernova on merging.