The origin of the planetary nebula M 1–16

Abstract

We investigated the origin of the Planetary Nebula (PN) M 1–16 using narrow-band optical imaging, and high- and low-resolution optical spectra to perform a detailed morpho-kinematic and chemical studies. M 1–16 is revealed to be a multipolar PN that predominantly emits in [O III] in the inner part of the nebula and [N II] in the lobes. A novel spectral unsharp masking technique was applied to the position-velocity (PV) maps to reveal a set of multiple structures at the centre of M 1–16 spanning radial velocities from −40 km s−1 to 20 km s−1, with respect to the systemic velocity. The morpho-kinematic model indicates that the deprojected velocity of the lobe outflows are ≥100 km s−1, and particularly the larger lobes and knots have a deprojected velocity of ≃350 km s−1; the inner ellipsoidal component has a deprojected velocity of ≃29 km s−1. A kinematical age of ~8700 yr has been obtained from the model assuming a homologous velocity expansion law and a distance of 6.2 ± 1.9 kpc. The chemical analysis indicates that M 1–16 is a Type I PN with a central star of PN (CSPN) mass in the range of ≃0.618 – 0.713 M⊙ and an initial mass for the progenitor star between 2.0 and 3.0 M⊙ (depending on metallicity). An Teff ≃ 140 000 K and log(L/L⊙) = 2.3 was estimated using the 3MdB photoionisation models to reproduce the ionisation. stage of the PN. All of these results have led us to suggest that M 1–16 is an evolved PN, contrary to the scenario of proto-PN suggested in previous studies. We propose that the mechanism responsible for the morphology of M 1–16 is related to the binary (or multiple star) evolution scenario.