Bipolar rings from jet-inflated bubbles around evolved binary stars

TL;DR

This paper models how bipolar rings around evolved binary stars can form through jet-inflated bubbles and fast winds, using 3D hydrodynamical simulations to explore nebula structures.

Contribution

It introduces a new model combining multiple mass loss episodes and jet interactions to explain bipolar ring formation around giant stars.

Findings

Bipolar rings can form from jet-inflated bubbles and fast winds in binary systems.

The model explains some planetary nebulae morphologies but not all features of SN1987A.

Pre-jets mass loss episodes may be necessary to reproduce certain observed structures.

Abstract

We show that a fast wind that expands into a bipolar nebula composed of two opposite jet-inflated bubbles can form a pair of bipolar rings around giant stars. Our model assumes three mass loss episodes: a spherical slow and dense shell, two opposite jets, and a spherical fast wind. We use the FLASH hydrodynamical code in three-dimensions to simulate the flow, and obtain the structure of the nebula. We assume that the jets are launched from an accretion disk around a stellar companion to the giant star. The accretion disk is assumed to be formed when the primary giant star and the secondary star suffer a strong interaction accompanied by a rapid mass transfer process from the primary to the secondary star, mainly a main sequence star. Later in the evolution the primary star is assumed to shrink and blow a fast tenuous wind that interacts with the dense gas on the surface of the bipolar structure. We assume that the dense mass loss episode before the jets are launched is spherically symmetric. Our results might be applicable to some planetary nebulae, and further emphasize the large variety of morphological features that can be formed by jets. But we could not reproduce some of the properties of the outer rings of SN1987A. It seems that some objects, like SN1987A, require a pre-jets mass loss episode with a mass concentration at mid-latitudes.