Keele Research Repository

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’ 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.