Diffuse X-ray Emission within Wolf-Rayet Nebulae

Abstract

We discuss our most recent findings on the diffuse X-ray emission from Wolf-Rayet (WR) nebulae. The best-quality X-ray observations of these objects are those performed by XMM-Newton and Chandra towards S308, NGC2359, and NGC6888. Even though these three WR nebulae might have different formation scenarios, they all share similar characteristics: i) the main plasma temperatures of the X-ray-emitting gas is found to be $T$=[1-2]$\times$10${}^6$ K, ii) the diffuse X-ray emission is confined inside the [O III] shell, and iii) their X-ray luminosities and electron densities in the 0.3-2.0~keV energy range are $L_{\mathrm{X}}\approx$10${}^{33}$-10${}^{34}$~erg~s${}^{-1}$ and $n_{\mathrm{e}}\approx$0.1-1~cm${}^{-3}$, respectively. These properties and the nebular-like abundances of the hot gas suggest mixing and/or thermal conduction is taking an important role reducing the temperature of the hot bubble.

3 pages, 1 figure; International Workshop on Wolf-Rayet Stars