3D spatio-kinematic modelling of Abell 48, a planetary nebula around a Wolf–Rayet [WN] star

Abstract

ABSTRACT The planetary nebula (PN) Abell 48 (PN G029.0+00.4) is around a rare Wolf–Rayet [WN5] star whose stellar history is as yet unknown. Using the integral field observations of the H αλ6563 and [N ii] λ6584 line emissions, we conducted a comprehensive spatio-kinematic analysis of this PN. A three-dimensional spatio-kinematic ionization model was developed with the kinematic modelling tool shape to replicate the observed spatially resolved velocity channels and position–velocity diagrams. According to our kinematic analysis of the H α emission, this object possesses a deformed elliptic toroidal shell with an outer radius of 23 arcsec and a thickness of 15 arcsec associated with an integrated H α emission-line expansion of ∼35 ± 5 km s−1, a maximum poloidal expansion of around 70 ± 20 km s−1 at an inclination angle of ∼30° with respect to the line of sight, and a position angle of ∼130° measured from east towards north in the equatorial coordinate system. Furthermore, [N ii] kinematic modelling reveals the presence of narrow (∼3 arcsec) exterior low-ionization structures surrounding the main elliptical shell, which could have formed as a result of shock collisions with the interstellar medium. The torus-shaped morphology of this PN could be related to its unusual hydrogen-deficient [WN] nucleus that needs to be inspected further.