Detailed studies of IPHAS sources -- I. The disrupted late bipolar
  IPHASX J193718.6+202102
  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 photoionisation
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$\pm$5 km s$^{-1}$ and is gradually
breaking up. At an estimated distance of 7.1$_{-0.3}^{+0.8}$ kpc, the
corresponding kinematic age of $\sim$26000 years is consistent with a faint and
disintegrating PN. The intermediate-resolution spectra reveal an excited PN
with chemical abundances typical of Type II PNe. Based on the latter we also
estimate an initial mass for the progenitor in the range 2--3 M$_{\odot}$ and a
central star (CSPN) mass $M_\mathrm{CSPN}\sim$0.61 M$_{\odot}$. The Spitzer
MIPS 24 $\mu$m emission that closely follows the fragmented torus could be
attributed to the emission of [O IV] at 25.9 $\mu$m 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.
