Modeling the diffuse X-ray emission of Planetary Nebulae with different chemical composition

TL;DR

This study uses radiation-hydrodynamics simulations to explore how the diffuse X-ray emission of planetary nebulae depends on their evolutionary stage, central star mass, metallicity, and thermal conduction effects, comparing results with observations.

Contribution

It provides a systematic analysis of the factors influencing X-ray emission in planetary nebulae, including the impact of chemical composition and thermal conduction, with models resembling Wolf-Rayet central stars.

Findings

Models with Wolf-Rayet type central stars produce the highest X-ray luminosities.

X-ray emission depends on nebular evolution, stellar mass, and metallicity.

Thermal conduction treatment significantly affects model predictions.

Abstract

Based on time-dependent radiation-hydrodynamics simulations of the evolution of Planetary Nebulae (PNe), we have carried out a systematic parameter study to address the non-trivial question of how the diffuse X-ray emission of PNe with closed central cavities is expected to depend on the evolutionary state of the nebula, the mass of the central star, and the metallicity of stellar wind and circumstellar matter. We have also investigated how the model predictions depend on the treatment of thermal conduction at the interface between the central `hot bubble' and the `cool' inner nebula, and compare the results with recent X-ray observations. Our study includes models whose properties resemble the extreme case of PNe with Wolf-Rayet type central stars. Indeed, such models are found to produce the highest X-ray luminosities.