Related papers: X-ray Emission from Ionized Wind-Bubbles around Wo…
Nearly all types of massive stars with radiatively driven stellar winds are X-ray sources that can be observed by the presently operating powerful X-ray telescopes. In this review I briefly address recent advances in our understanding of…
We present hydrodynamical simulations of galactic winds from star-forming galaxies including non-equilibrium ionization and frequency-dependent radiative transfer, processes that have remained largely unaccounted for in galactic wind…
WR 140 is a long-period, highly eccentric Wolf-Rayet star binary system with exceptionally well-determined orbital and stellar parameters. Bright, variable X-ray emission is generated in shocks produced by the collision of the winds of 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…
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…
Observations with powerful X-ray telescopes, such as XMM-Newton and Chandra, significantly advance our understanding of massive stars. Nearly all early-type stars are X-ray sources. Studies of their X-ray emission provide important…
We calculate the X-ray emission from both constant and time evolving shocked fast winds blown by the central stars of planetary nebulae (PNs) and compare with observations. Using spherically symmetric numerical simulations with radiative…
We present a simple analytical method to describe the structure of a spherically expanding envelope with strong mass outflow. The structure is consistently connected to the hydrostatic stellar interior and provides an adequate description…
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…
Photospheric radius expansion during X-ray bursts can be used to measure neutron star radii and help constrain the equation of state of neutron star matter. Understanding the stellar wind dynamics is important for interpreting observations.…
We present a morphological study of nebulae around Wolf-Rayet (WR) stars using archival narrow-band optical and Wide-field Infrared Survey Explorer (WISE) infrared images. The comparison among WISE images in different bands and optical…
We use WR124 (WN8h) and its associated nebula M1-67, to test theoretical non-LTE models for Wolf-Rayet (WR) stars. Lyman continuum ionizing flux distributions derived from a stellar analysis of WR124, are compared with nebular properties…
Vigorous mass loss in the classical Wolf-Rayet (WR) phase is important for the late evolution and final fate of massive stars. We develop spherically symmetric time-dependent and steady-state hydrodynamical models of the radiation-driven…
Wolf-Rayet stars are advanced evolutionary stages of massive stars. Despite their large mass-loss rates and high wind velocities, none of them display a bow shock, although a fraction of them are classified as runaway. Our 2.5-D numerical…
The clumping of massive star winds is an established paradigm confirmed by multiple lines of evidence and supported by stellar wind theory. The purpose of this paper is to bridge the gap between detailed models of inhomogeneous stellar…
Gamma-ray observations of young star clusters have recently provided evidence for particle acceleration occurring at stellar wind termination shocks, fueled by the mechanical energy of stellar winds from massive stars. In this work, we…
Wolf-Rayet (WR) stars are evolved massive stars with strong fast stellar winds. WR stars in our Galaxy have shown three possible sources of X-ray emission associated with their winds: shocks in the winds, colliding stellar winds, and…
We present a study of the X-ray emission from numerical simulations of hot bubbles in planetary nebulae (PNe). High-resolution, two-dimensional, radiation-hydrodynamical simulations of the formation and evolution of hot bubbles in PNe, with…
From stellar evolution models and from observations of Wolf-Rayet stars it is known that massive stars are releasing metal-enriched gas in their Wolf-Rayet phase by means of strong stellar winds. Although HII region spectra serve as…
Winds from young massive stars contribute a large amount of energy to their host molecular clouds. This has consequences for the dynamics and observable structure of star-forming clouds. In this paper, we present radiative…