Multipolar Planetary Nebulae: Not as Geometrically Diversified as Thought

TL;DR

This paper demonstrates that many complex planetary nebulae can be explained by a multipolar model with three pairs of lobes, suggesting such structures are more common than previously thought.

Contribution

It introduces a simple six-parameter model to reproduce the observed morphologies of complex PNe, challenging previous assumptions about their diversity.

Findings

A multipolar model explains many PNe features.

The true prevalence of multipolar PNe has been underestimated.

A small set of parameters can reproduce complex nebulae images.

Abstract

Planetary nebulae (PNe) have diverse morphological shapes, including point-symmetric and multipolar structures. Many PNe also have complicated internal structures such as torus, lobes, knots, and ansae. A complete accounting of all the morphological structures through physical models is difficult. A first step toward such an understanding is to derive the true three-dimensional structure of the nebulae. In this paper, we show that a multipolar nebula with three pairs of lobes can explain many of such features, if orientation and sensitivity effects are taken into account. Using only six parameters - the inclination and position angles of each pair - we are able to simulate the observed images of 20 PNe with complex structures. We suggest that the multipolar structure is an intrinsic structure of PNe and the statistics of multipolar PNe has been severely underestimated in the past.