Related papers: A Radio Pinwheel Emanating from WR147
Massive stars are powerful cosmic engines. In the phases immediately preceding core-collapse, massive stars in the Galaxy with $M_i \gtrsim 20$ $M_{\odot}$ may appear as classical Wolf-Rayet (WR) stars. As the final contribution of a…
Wolf-Rayet (WR) stars are massive stars that have lost most or all of their hydrogen via powerful stellar winds. Recent observations have indicated that hydrogen-free WR stars have cooler temperatures than those predicted by current…
In 1997 and 2008 we used the WFPC2 camera on board of the Hubble Space Telescope to obtain two sets of narrow-band H$\alpha$ images of the runaway Wolf-Rayet (WR) star WR 124 surrounded by its nebula M1-67. This two-epoch imaging provides…
We present calculations of the spatial and spectral distribution of the radio emission from a wide WR+OB colliding-wind binary system based on high-resolution hydrodynamical simulations and solutions to the radiative transfer equation. We…
Most massive stars reside in multiple systems that will interact over the course of their lifetime. Classical Wolf-Rayet (WR) stars represent the final end stages of stellar evolution at the upper-mass end. As part of a homogeneous,…
Because most massive stars have been or will be affected by a companion during the course of their evolution, we cannot afford to neglect binaries when discussing the progenitors of supernovae and GRBs. Analyzing linear polarization in the…
This work aims to disentangle the morphological, kinematic, and chemical components of the nebula M1-67 to shed light on its process of formation around the central Wolf-Rayet (WR) star WR124. We have carried out integral field spectroscopy…
Aims: Following our comprehensive studies of the WR stars in the Milky Way, we now present spectroscopic analyses of almost all known WN stars in the LMC. Methods: For the quantitative analysis of the wind-dominated emission-line spectra,…
Context. Massive-binary evolution models predict that some systems will go through an evolutionary phase where the original primary has become a supernova and left a compact object behind that then orbits a Wolf-Rayet (hereafter, WR) star.…
We explore the ability of high energy observations to constrain orbital parameters of long period massive binary systems by means of an inverse Compton model acting in colliding wind environments. This is particular relevant for (very) long…
Given their strong stellar winds, Wolf-Rayet (WR) stars exhibit emission line spectra that are predominantly formed in expanding atmospheric layers. The description of the wind velocity field $v(r)$ is therefore a crucial ingredient in the…
The hot WN star WR2 (HD6327) has been claimed to have many singular characteristics. To explain its unusually rounded and relatively weak emission line profiles, it has been proposed that WR2 is rotating close to break-up with a…
Infrared photometry of the probable triple WC4(+O?)+O8I: Wolf-Rayet system HD 36402 (= BAT99-38) in the Large Magellanic Cloud (LMC) shows emission characteristic of heated dust. The dust emission is variable on a time-scale of years, with…
We study relatively isolated massive WN-type stars in the Galactic center. The K-band spectra of WR102ka and WR102c are exploited to infer the stellar parameters and to compute synthetic stellar spectra using the Potsdam Wolf-Rayet (PoWR)…
We present the analysis of observations taken from the Very Large Array archive of six Wolf-Rayet stars with radio emission, with the purpose of determining their proper motions. Typically, these observations cover periods of 10 to 20…
Examination of the temporal variability properties of several strong optical recombination lines in a large sample of Galactic Wolf-Rayet (WR) stars reveals possible trends, especially in the more homogeneous WC than the diverse WN…
The final explosive fate of massive stars, and the nature of the compact remnants they leave behind (black holes and neutron stars), are major open questions in astrophysics. Many massive stars are stripped of their outer hydrogen envelopes…
We analyzed 64 radio observations at the frequency of 8.4 GHz of the Wolf-Rayet star WR 112, taken from the Very Large Array archive. These observations cover a time baseline of 13 years, from June 2000 to July 2013. The radio structure of…
Wolf-Rayet (WR) stars have a severe impact on their environments owing to their strong ionizing radiation fields and powerful stellar winds. Since these winds are considered to be driven by radiation pressure, it is theoretically expected…
Radio observations are an effective tool to discover particle acceleration regions in colliding-wind binaries, through detection of synchrotron radiation; these regions are natural laboratories for the study of relativistic particles.…