Related papers: Dust formation by the colliding-wind WC5+O9 binary…

We present high-resolution infrared (2--18 micron) images of the archetypal periodic dust-making Wolf-Rayet binary system WR140 (HD 193793) taken between 2001 and 2005, and multi-colour (J -- [19.5]) photometry observed between 1989 and…

Several long-period binaries with a carbon-rich Wolf-Rayet star and an O star produce dust in their wind collisions. In eccentric binaries, this is seen most strongly near periastron passage. The exact conditions leading to dust creation…

We have carried out a long term infrared and X-ray investigation of the colliding wind binary WR 125 (WC7+O9III). The source was monitored using AstroSat-Soft X-ray Telescope and TIRCAM2 mounted at the back of 3.6 m Devasthal Optical…

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…

Observations of the WC9+OB system WR 65 in the infrared show variations of its dust emission consistent with a period near 4.8~yr, suggesting formation in a colliding-wind binary (CWB) having an elliptical orbit. If we adopt the IR maximum…

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.…

Wolf-Rayet (WR) 140 is the archetypal periodic dust-forming colliding-wind binary that hosts a carbon-rich WR (WC) star and an O-star companion with an orbital period of 7.93 years and an orbital eccentricity of 0.9. Throughout the past…

WR 137 (HD 192641) is a binary system consisting of a carbon-rich Wolf-Rayet star and an Oe companion star in a 13-year orbit. Near periastron, the winds of the two stars collide and form carbonaceous dust. We obtained three mid-infrared…

The Wolf-Rayet (WR) binary system WR140 is a close (0.9-16.7 mas) binary star consisting of an O5 primary and WC7 companion and is known as the archetype of episodic dust-producing WRs. Dust in WR binaries is known to form in a confined…

The eccentric WR+O binary system WR 140 produces dust for a few months at intervals of 7.94 yrs coincident with periastron passage. We present the first resolved images of this dust shell, at binary phases ~0.039 and ~0.055, using aperture…

Classical Wolf-Rayet stars are the descendants of massive OB stars that have lost their hydrogen envelopes and are burning helium in their cores prior to exploding as type Ib/c supernovae. The mechanisms for losing their hydrogen envelopes…

We discovered that the Wolf-Rayet (WR)+OB star binary, WR 104, renowned for its associated "dusty pinwheel nebula" recently spatially resolved with infrared interferometry, exhibits strong quasi-periodic optical variations with a full…

Carbon-rich Wolf-Rayet (WR) stars are significant contributors of carbonaceous dust to the galactic environment, however the mechanisms and conditions for formation and subsequent evolution of dust around these stars remain open questions.…

The colliding wind binary WR140 produces dust in its shocked gas every periastron passage. While the infrared light curve is very repeatable, there are noticeable changes every cycle in the optical time-series photometry. In the phases…

Carbon-rich Wolf-Rayet binaries are a prominent source of carbonaceous dust that contribute to the dust budget of galaxies. The "textbook" example of an episodic dust producing WR binary, WR140 (HD193793), provides us with an ideal…

Massive colliding-wind binaries that host a Wolf-Rayet (WR) star present a potentially important source of dust and chemical enrichment in the interstellar medium (ISM). However, the chemical composition and survival of dust formed from…

We present new spectra of WR 140 (HD 193793) in the JHK bands with some covering the 1.083-micron He I emission line at higher resolution, observed between 2000 October and 2003 May to cover its 2001 periastron passage. The WC7 + O4-5…

We present Spitzer/IRAC observations of dust formation from six extragalactic carbon-rich Wolf-Rayet (WC) binary candidates in low-metallicity (Z $\lesssim0.65$ Z$_\odot$) environments using multi-epoch mid-infrared (IR) imaging data from…

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…

We present infrared photometry of the WC8 Wolf-Rayet system WR 48a observed with telescopes at ESO, the SAAO and the AAT between 1982 and 2011 which show a slow decline in dust emission from the previously reported outburst in 1978--79…