Related papers: Theoretical considerations on colliding clumped wi…
X-ray spectroscopy is a sensitive probe of stellar winds. X-rays originate from optically thin shock-heated plasma deep inside the wind and propagate outwards throughout absorbing cool material. Recent analyses of the line ratios from…
Mass-loss rates currently in use for hot, massive stars have recently been seriously questioned, mainly because of the effects of wind clumping. We investigate the impact of clumping on diagnostic ultraviolet resonance and optical…
The high luminosity of massive, early-type stars drives strong stellar winds through line scattering of the stars continuum radiation. Their momenta contribute substantially to the dynamics and energetics of the ambient interstellar medium…
The colliding wind binary (CWB) systems \eta\ Carinae and WR140 provide unique laboratories for X-ray astrophysics. Their wind-wind collisions produce hard X-rays that have been monitored extensively by several X-ray telescopes, including…
Colliding winds of massive stars in binary systems are considered as candidate sites of high-energy non-thermal photon emission. They are already among the suggested counterparts for a few individual unidentified EGRET sources, but may…
We review recent developments regarding radiation driven mass loss from OB-stars. We first summarize the fundamental theoretical predictions, and then compare these to observational results (including the VLT-FLAMES survey of massive…
Polarization provides additional diagnostic opportunities for probing the structured environments of massive stars as well as the illumination of those environments by stars that are not spherical. After a brief overview of polarization…
Abridged: We study the properties of clumps formed in three-dimensional weakly magnetized magneto-hydrodynamic simulations of converging flows in the thermally bistable, warm neutral medium (WNM). We find that: (1) Similarly to the…
WR146 is a WC6+O8 colliding-wind binary (CWB) system with thermal emission from the stellar winds of the two stars, and bright non-thermal emission from the wind-collision region (WCR) where the winds collide. We present high resolution…
As massive stars evolve, their winds change. This causes a series of hydrodynamical interactions in the surrounding medium. Whenever a fast wind follows a slow wind phase, the fast wind sweeps up the slow wind in a shell, which can be…
Recent progress in the understanding of star formation is summarized. A consistent picture is emerging where molecular clouds form with turbulent velocity fields and clumpy substructure, imprinted already during their formation. The clouds…
Stellar winds form an integral part of astronomy. The solar wind affects Earth's magnetosphere, while the winds of hot massive stars are highly relevant for galactic feedback through their mechanical wind energy. In different parts of the…
The wind collision region (WCR) in a colliding wind binary (CWB) is a particularly violent place, as such, it is surprising that it is also a region where significant quantities of interstellar dust can form. In extreme cases, approximately…
The classical model for free-free emission from ionized stellar winds is based on the assumption of a stationary, isotropic and homogeneous wind. However, since there exist objects whose wind behaviour deviates from the standard model,…
The intricate interplay of atmospheric shock waves and a complex, variable radiation field with non-equilibrium dust formation presents a considerable challenge to self-consistent modelling of atmospheres and winds of AGB stars.…
The progress over the last years in modelling the atmospheres and winds of PN central stars is reviewed. We discuss the effect of the inclusion of the blanketing by millions of metal lines in NLTE on the diagnostics of photospheric and…
We investigate giant molecular cloud (GMCs) collisions and their ability to induce gravitational instability and thus star formation. This mechanism may be a major driver of star formation activity in galactic disks. We carry out a series…
In young star clusters, the density can be high enough and the velocity dispersion low enough for stars to collide and merge with a significant probability. This has been suggested as a possible way to build up the high-mass portion of the…
Molecular clouds in the interstellar medium suffer gravitational instabilities that lead to the formation of one or multiple stars. A recently formed star inside a cold cloud communicates its gravitational force to the surrounding…
Forming planets around young, fast-rotating solar-like stars are exposed to an intense X-ray/extreme ultraviolet radiation field and strongly magnetized stellar winds, as a consequence of the high magnetic activity of these stars. Under…