Related papers: Asymmetric Wolf-Rayet winds: implications for GRB …
We review the properties of carbon-sequence ([WC]) Wolf-Rayet central stars of planetary nebulae (CSPNe). Differences between the subtype distribution of [WC] stars and their massive WC cousins are discussed. We conclude that [WO]-type…
The association of long gamma-ray bursts (GRBs) with star forming regions and the idea of massive stars as progenitors of GRBs are widely accepted. Because of their short lifetimes, it is very likely that massive stars are still embedded in…
Supergiant High Mass X-ray Binary systems (sgHMXBs) consist of a massive, late type, star and a neutron star. The massive stars exhibits strong, radiatively driven, stellar winds. Wind accretion onto compact object triggers X-ray emission,…
We report the discovery of variability in the X-ray emission from the Wolf-Rayet type star WR 65. Using archival Chandra data spanning over 5 yr we detect changes of the X-ray flux by a factor of 3 accompanied by changes in the X-ray…
The Wolf-Rayet (WR) phenomenon is widespread in astronomy. It involves classical WRs, very massive stars (VMS), WR central stars of planetary nebula CSPN [WRs], and supernovae (SNe). But what is the root cause for a certain type of object…
A handful of binary Wolf-Rayet stars are known to harbour spectacular spiral structures spanning a few hundred AU. These systems host some of the highest dust production rates in the Universe and are therefore interesting candidates to…
The X-ray afterglows of almost one half of gamma-ray bursts have been discovered to have a shallow decay phase by the {\em Swift} satellite, whose origin remains mysterious. Two main models have been proposed to explain this phase,…
The energy requirements of gamma ray bursts have in past been poorly constrained because of three major uncertainties: The distances to bursts, the degree of burst beaming, and the efficiency of gamma ray production. The first of these has…
I propose that the moving `wisps' near the center of the Crab Nebula result from nonlinear Kelvin-Helmholtz instabilities in the equatorial plane of the shocked pulsar wind. Recent observations suggest that the wisps trace out circular…
Context. The structure of the wind from the cool giants in symbiotic binaries carries important information for understanding the wind mass transfer to their white dwarf companions and its fuelling. Aims. In this paper, we indicate a…
WR 20a is the most massive close-in binary known in our Galaxy. It is composed of two $\approx$80 M$_\odot$ Wolf-Rayet stars with a short period of $\approx$3.7 days in the open cluster Westerlund 2. As such, WR 20a presents us with a…
By analogy with the solar system, it is believed that stellar winds will form bow shocks around exoplanets. For hot Jupiters the bow shock will not form directly between the planet and the star, causing an asymmetric distribution of mass…
The mass loss from Wolf-Rayet (WR) stars is of fundamental importance for the final fate of massive stars and their chemical yields. Its Z-dependence is discussed in relation to the formation of long-duration Gamma Ray Bursts (GRBs) and the…
The collapse of a massive star is believed to be the most probable progenitor of a long GRB. Such a star is expected to modify its environment by stellar wind. The effect of such a circum-stellar wind medium is expected to be seen in the…
Wolf-Rayet (WR) stars are luminous massive blue stars thought to be immediate precursors to the supernova terminating their brief lives. The existence of dust shells around such stars has been enigmatic since their discovery some 30 years…
Context:A significant fraction of progenitors for long gamma-ray bursts (GRBs) are believed to be massive stars. The investigation of long GRBs therefore requires modeling the propagation of ultra-relativistic blastwaves through the…
Winds from massive stars (> 8 solar masses) result in the formation of wind-blown "bubbles" around these stars. In this paper we study, via two-dimensional numerical hydrodynamic simulations, the onset and growth of turbulence during the…
Observations of nearby molecular clouds detect "shells", which are likely caused by winds from young main sequence stars. However, the progenitors of these observed features are not well characterized and the mass-loss rates inferred from…
The Galactic centre is a hotbed of astrophysical activity, with the injection of wind material from $\sim$30 massive Wolf-Rayet (WR) stars orbiting within 12" of the super-massive black hole (SMBH) playing an important role. Hydrodynamic…
Short Gamma-Ray Bursts (GRBs) are known to be associated with binary neutron star (NSNS) or black hole-neutron star (BHNS) mergers. The detection of gravitational wave and its associated electromagnetic counterparts GW/GRB 170817A has shown…