From Bipolar to Elliptical: Morphological Changes in the Temporal Evolution of PN

TL;DR

This study uses 2.5D hydrodynamical simulations to explore how episodic wind interactions from AGB stars lead to the morphological evolution of planetary nebulae from bipolar to elliptical shapes over time.

Contribution

It introduces a detailed simulation framework that models the transition of nebulae morphologies driven by episodic wind changes and investigates the effects of different stellar wind parameters.

Findings

Simulations reproduce realistic PN dynamics and morphologies.

Episodic wind changes can explain the bipolar to elliptical transition.

Different AGB distributions and jet cycles influence nebula shapes.

Abstract

Proto-planetary nebulae (pPN) and planetary nebulae (PN) seem to be formed by interacting winds from asymptotic giant branch (AGB) stars. The observational issue that most pPN are bipolar but most older PN are elliptical is addressed. We present 2.5D hydrodynamical numerical simulations of episodic cooling interacting winds to investigate the long term evolution of PN morphologies. We track wind acceleration, decrease in mass-loss and episodic change in wind geometry from spherical (AGB) to collimated (pPN) and back to spherical again (PN). This outflow sequence is found to produce realistic PN dynamics and morphological histories. Effects from different AGB distributions and jet duty cycles are also investigated.