Spatio-kinematic modelling: Testing the link between planetary nebulae and close binaries

TL;DR

This study models planetary nebulae with close binary central stars to test if their orientations support the theory that binaries shape nebulae, providing observational evidence for the binary shaping hypothesis.

Contribution

It presents the most recent models of nebulae with close binary stars, confirming the perpendicular orientation between nebulae and binary planes, supporting the binary shaping hypothesis.

Findings

All modeled nebulae have symmetry axes perpendicular to binary planes.

The results support the hypothesis that binaries influence nebula morphology.

Future models may reveal trends linking nebula and binary parameters.

Abstract

It is widely believed that central star binarity plays an important role in the formation and evolution of aspherical planetary nebulae, however observational support for this hypothesis is lacking. Here, we present the most recent results of a continuing programme to model the morphologies of all planetary nebulae known to host a close binary central star. Initially, this programme allows us to compare the inclination of the nebular symmetry axis to that of the binary plane, testing the theoretical expectation that they will lie perpendicular - to date, all have satisfied this expectation, indicating that each nebula has been shaped by its central binary star. As a greater sample of nebulae are modelled, it will be possible to search for trends connecting the parameters of both nebula and central binary, strengthening our understanding of the processes at work in these objects. I will discuss some of the more obvious comparisons, and their current statuses, as well as the obvious links to common envelope evolution.