Related papers: A new Wolf-Rayet star in Cygnus
We have detected 58 Wolf-Rayet candidates in the central region of the nearby spiral galaxy NGC 300, based on deep VLT-FORS2 narrow-band imaging. Our survey is close to complete except for heavily reddened WR stars. Of the objects in our…
New NTT/SOFI imaging and spectroscopy of the Wolf-Rayet population in Westerlund 1 are presented. Narrow-band near-IR imaging together with follow up spectroscopy reveals four new WR stars, of which three were independently identified…
The similarity in physical conditions in winds of low-mass post-asymptotic giant branch stars and evolved massive stars leads to the appearance of an interesting phenomenon of spectral mimicry. Due to that the discovery of every new star…
Gravitationally bound companions to stars enable determinations of their masses, and offer clues to their formation, evolution and dynamical histories. So motivated, we have carried out a speckle imaging survey of eight of the nearest and…
We attempt to determine the driver for clumping in hot-star winds by extending the measure of the spectral variability level of Galactic Wolf-Rayet stars to by far the hottest known among them, the WN2 star WR 2 and the WO2 stars WR 102 and…
With the High Resolution Spectrograph aboard the Hubble Space Telescope we obtained high signal-to-noise (S/N > 200 - 600 per 17 km/s resolution element) spectra of narrow absorption lines toward the Wolf-Rayet star HD 50896. The ring…
We present new radio and optical observations of the colliding-wind system WR146 aimed at understanding the nature of the companion to the Wolf-Rayet star and the collision of their winds. The radio observations reveal emission from three…
We here report the properties of Wolf-Rayet (W-R) stars in 14 locations in the nearby spiral galaxy M81. These locations were found serendipitously while analysing the slit spectra of a sample of ~150 star-forming complexes, taken using 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…
Determining the Galactic distribution and numbers of massive stars, such as Wolf-Rayet stars (WRs), is hampered by intervening Galactic or local circumstellar dust obscuration. In order to probe such regions of the Galaxy we can use…
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 observed the Blue Compact Dwarf/Wolf-Rayet galaxy Mrk 178 with the NICMOS camera aboard HST. The galaxy is well resolved into individual stars in the near-IR; photometry in J and H yields color-magnitude diagrams containing 791…
Wolf-Rayet (WR) stars comprise a class of stars whose spectra are dominated by strong, broad emission lines that are associated with copious mass loss. In the massive-star regime, roughly 90% of the known WR stars are thought to have…
We present mid-infrared spectrophotometric results obtained with the ISO on the peculiar X-ray binary Cygnus X-3 in quiescence, at orbital phases 0.83 to 1.04. The 2.4-12 microns continuum radiation observed with ISOPHOT-S can be explained…
Massive Wolf-Rayet (WR) stars comprise a spectroscopic class characterized by high temperatures (Teff > ~30 kK) and powerful and rapid stellar winds. Hydrogen-rich WR stars represent the most massive stars in existence (M > ~100 Msun),…
The Wolf-Rayet (WR) nebula NGC3199 has been suggested to be a bow shock around its central star WR18, presumably a runaway star, because optical images of the nebula show a dominating arc of emission south-west of the star. We present the…
Recent large scale Galactic Plane H$\alpha$ surveys allow a re-examination of the environs of Wolf-Rayet (WR) stars for the presence of a circumstellar nebula. Using the morphologies of WR nebulae known to be composed of stellar ejecta as a…
Wolf-Rayet stars represent one of the final stages of massive stellar evolution. Relatively little is known about this short-lived phase and we currently lack reliable mass, distance, and binarity determinations for a representative sample.…
Previous studies have demonstrated that putatively single nitrogen-type Wolf-Rayet stars (WN stars) without known companions are X-ray sources. However, almost all WN star X-ray detections so far have been of earlier WN2 - WN6 spectral…
Results: The two Wolf-Rayet stars WR20a (WN6ha+WN6ha) and WR20b (WN6ha) were analyzed in detail. They are both very luminous and display very hard spectra, but WR20b does not seem to vary. On the contrary, WR20a, a known eclipsing,…