2021MNRAS.501.3582S

We present a detailed analysis of the new planetary nebula (PN) IPHASX J193718.6+202102 using deep imaging and intermediate- and high-resolution spectroscopy that are interpreted through morpho-kinematic and photoionization modelling. The physical structure of the nebula consists of a fragmented torus and an extremely faint orthogonal bipolar outflow, contrary to the pinched waist PN morphology suggested by its optical image. Our kinematic analysis indicates that the torus is expanding at 25 ± 5 km s^–1 and is gradually breaking up. At an estimated distance of 7.1_–0.3^+0.8 kpc, the corresponding kinematic age of ∼26 000 yr is consistent with a faint and disintegrating PN. The intermediate-resolution spectra reveal an excited PN with chemical abundances typical of Type II PNe. Based on the latter, we also estimate an initial mass for the progenitor in the range 2-3 M_☉ and a central star (CSPN) mass M_CSPN ∼0.61 M_☉. The Spitzer MIPS 24 µm emission that closely follows the fragmented torus could be attributed to the emission of [O IV] at 25.9 µm rather than to dust emission. All the results coherently point towards an evolved moderately massive bipolar Type II PN on the brink of dissolving into the interstellar medium.