CK Vul: a smorgasbord of hydrocarbons rules out a 1670 nova (and much else besides)

TL;DR

This study uses Spitzer infrared observations to analyze CK Vul, ruling out several previous hypotheses about its nature and highlighting the complexity of its composition, leaving its true identity unresolved.

Contribution

The paper provides detailed infrared spectral data of CK Vul, challenging prior classifications and suggesting it is not a classical nova remnant or related phenomena, thus refining its astrophysical understanding.

Findings

Infrared spectrum shows warm dust, nebular, molecular hydrogen, and HCN lines.

Data incompatible with CK Vul being a classical nova remnant or similar objects.

The true nature of CK Vul remains unknown.

Abstract

We present observations of CK Vul obtained with the Spitzer Space Telescope. The infrared spectrum reveals a warm dust continuum with nebular, molecular hydrogen and HCN lines superimposed, together with the "Unidentified Infrared" (UIR) features. The nebular lines are consistent with emission by a low density gas. We conclude that the Spitzer data, combined with other information, are incompatible with CK Vul being a classical nova remnant in "hibernation" after the event of 1670, a "Very Late Thermal Pulse", a "Luminous Red Variable" such as V838 Mon, or a "Diffusion-induced nova". The true nature of CK Vul remains a mystery.