Forming H-shaped and barrel-shaped nebulae with interacting jets

TL;DR

This study uses 3D hydrodynamical simulations to demonstrate how interacting jets from binary stars can produce nebulae with barrel-like and H-shaped morphologies, matching observations of planetary nebulae.

Contribution

It introduces a new model showing how jet-shell interactions in binary systems can create specific nebular shapes observed in space.

Findings

Jets can form H-shaped and barrel-shaped nebulae.

Morphologies evolve over time with complex flow patterns.

Simulation results match observed planetary nebulae images.

Abstract

We conduct three-dimensional hydrodynamical simulations of two opposite jets launched from a binary stellar system into a previously ejected shell and show that the interaction can form barrel-like and H-like shapes in the descendant nebula. Such features are observed in planetary nebulae and supernova remnants. Under our assumption the dense shell is formed by a short instability phase of the giant star as it interacts with a stellar companion, and the jets are then launched by the companion as it accretes mass through an accretion disk from the giant star. We find that the H-shaped and barrel-shaped morphological features that the jets form evolve with time, and that there are complicated flow patterns, such as vortices, instabilities, and caps moving ahead along the symmetry axis. We compare our numerical results with images of 12 planetary nebulae, and show that jet-shell interaction that we simulate can account for the barrel-like or H-like morphologies that are observed in these PNe.