相关论文: Wolf-Rayet and LBV Nebulae as the Result of Variab…

We present Hubble Space Telescope WFPC2 images of a portion of the bright northeast rim of NGC 6888, the nebular shell physically associated with the Wolf-Rayet star HD 192163. The exposures are taken in the light of Halpha 6563, [O III]…

Massive evolved stars loss a large fraction of their mass via copious stellar wind or instant outbursts and during certain evolutionary phases they can be identified via the presence of their circumstellar nebulae. In this paper, we present…

Wolf-Rayet stars are amongst the rarest but also most intriguing massive stars. Their extreme stellar winds induce famous multi-wavelength circumstellar gas nebulae of various morphologies, spanning from circles and rings to bipolar shapes.…

The stellar winds of massive stars show large changes in mass-loss rates and terminal velocities during their evolution from O-star through the Luminous Blue Variable phase to the Wolf-Rayet phase. The luminosity remains approximately…

Stellar winds emitted by rotating massive stars may show two main components: firstly bipolar lobes with low density and fast wind, produced by the higher T$_{\mathrm{eff}}$ and gravity at the poles (`g$_{\mathrm{eff}}$-effect'); secondly,…

I discuss some observational properties of aspherical nebulae around massive stars, and conclusions inferred for how they may have formed. Whether or not these ideas are applicable to the shaping of planetary nebulae is uncertain, but the…

(abridged) The strong winds of Wolf-Rayet (WR) stars are important for the mechanical and chemical feedback of the most massive stars and determine whether they end their lives as neutron stars or black holes. In this work we investigate…

This thesis discusses the influence of magnetic fields on the instability of line-driven winds in O-stars and Wolf-Rayet stars. This combination is an important concept to understand the strong, observed winds from Wolf-Rayet stars. In the…

We have observed H-alpha and [OIII] emission from eight of the most well defined Wolf-Rayet ring nebulae in the Galaxy. We find that in many cases the outermost edge of the [OIII] emission leads the H-alpha emission. We suggest that these…

Here we examine 12 Galactic clusters and OB associations containing Wolf-Rayet stars (W-Rs) and/or Luminous Blue Variables (LBVs), in order to assess the progentor masses of these evolved massive stars. We find that in the Milky Way,…

Line-driven stellar winds are ubiquitous among hot massive stars. In some cases they can become so strong, that the whole star is cloaked by an optically thick wind. The strong outflow gives rise to large emission lines, defining the class…

Over the past decade, the number of planetary nebula central stars (CSPN) known to exhibit the Wolf-Rayet (WR) phenomenon has grown substantially. Many of these discoveries have resulted from the Macquarie/AAO/Strasbourg Ha (MASH) PN…

The Wolf-Rayet (WR) phenomenon is widespread in astronomy. It involves classical WRs, very massive stars (VMS), WR central stars of planetary nebula CSPN [WRs], and supernovae (SNe). But what is the root cause for a certain type of object…

Using a code that employs a self-consistent method for computing the effects of photoionization on circumstellar gas dynamics, we model the formation of wind-driven nebulae around massive Wolf-Rayet (W-R) stars. Our algorithm incorporates a…

Luminous Blue Variables (LBVs) are believed to be evolved, extremely massive stars close to the Eddington Limit and hence prone to bouts of large-scale, unstable mass loss. I discuss current understanding of the evolutionary state of these…

We construct a speculative scenario for the evolution of Wolf-Rayet central stars of planetary nebula. It is clear from the latest infra-red observations that a new perspective has to be adopted: the simultaneous presence of carbon- and…

This review discusses the physics of the formation of planetary nebulae around low mass WR stars, or [WR] stars. It especially focuses on the differences which can be expected due to the different character of the fast winds from these [WR]…

We seek to understand the evolution of Wolf-Rayet central stars by comparing the diffuse X-ray emission from their wind-blown bubbles with that from their hydrogen-rich counterparts with predictions from hydrodynamical models. We simulate…

Massive stars shape their surrounding medium through the force of their stellar winds, which collide with the circumstellar medium. Because the characteristics of these stellar winds vary over the course of the evolution of the star, the…

With their emission-line dominated spectra, the appearance of Wolf-Rayet stars is shaped by their strong stellar winds. Yet, the physical mechanisms behind their high mass loss have long remained enigmatic. While we know nowadays that…