相关论文: Wolf-Rayet stars

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…

Wolf-Rayet (WR) stars of the WNh category contain a significant fraction of hydrogen at their surface. They can be hydrogen-burning, very massive stars or stars in a post-main sequence phase of evolution. Also, WNh stars are sometimes not…

We present high resolution spectrophotometric data for 34 galactic planetary nebulae with [WC] nuclei (WRPNe).The sample includes PNe with early and late [WC] stars and some WELS. Physical conditions and chemical abundances have been…

Wolf-Rayet star's winds can be so dense and so optically thick that the photosphere appears in the highly supersonic part of the outflow, veiling the underlying subsonic part of the star, and leaving the initial acceleration of the wind…

Wolf-Rayet (WR) stars near solar metallicity are believed to be driven by radiation pressure on the UV spectral lines of metal ions. As the metallicity decreases so does the line opacity, therefore the mass-loss rate. However, since the…

We present here spatially-resolved optical spectroscopic observations of four nearby dwarf Wolf-Rayet (WR) galaxies. The ages of the most recent starburst events in these galaxies are found between 3 and 10 Myr. The gas-phase metallicities…

We will present results of studies of several massive stars at different evolutionary stages, but with similar values of the initial mass: O-supergiants belonging to association Cyg OB2, unique LBV/post-LBV - Romano's star and two…

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 report a spectroscopic search for hypervelocity white dwarfs (WDs) that are runaways from Type Ia supernovae (SNe Ia) and related thermonuclear explosions. Candidates are selected from Gaia data with high tangential velocities and blue…

We addressed the physical and kinematical properties of Wolf -- Rayet [WR] central stars (CSs) and their hosting planetary nebulae (PNe). The studied sample comprises all [WR] CSs that are currently known. The analysis is based on recent…

Most stars will experience episodes of substantial mass loss at some point in their lives. For very massive stars, mass loss dominates their evolution, although the mass loss rates are not known exactly, particularly once the star has left…

Massive stars shape their surrounding medium through the force of their stellar winds, which collide with the circumstellar medium. Because the characteristics of these stellar winds vary over the course of the evolution of the star, the…

Observed properties of GRBs, WR stars and their CO-cores in the end of evolution are analyzed. A possible bimodality of the observed GRB energy distribution ($10^{48}$ erg for GRB9809425; $3\times 10^{51}\div 2\times 10^{54}$ erg for…

We report the discovery of weak yet hard X-ray emission from the Wolf-Rayet (WR) star WR142 with the XMM-Newton X-ray telescope. Being of spectral subtype WO2, WR142 is a massive star in a very advanced evolutionary stage, short before its…

Based on $K$-band integral-field spectroscopy, we analyze four Wolf-Rayet stars of the nitrogen sequence (WN) found in the inner part of the Quintuplet cluster. All WN stars (WR102d, WR102i, WR102hb, and WR102ea) are of spectral subtype…

We report the discovery of additional hot and massive stars in the cluster surrounding the soft gamma repeater SGR 1806-20, based upon UKIRT and Keck near-infrared spectroscopy. Of the newly identified stars, three are Wolf-Rayet stars of…

The environments surrounding nine Wolf-Rayet stars were studied in molecular emission. Expanding shells were detected surrounding these WR stars (see left panels of Figure 1). The average masses and radii of the molecular cores surrounding…

The stellar properties of Sk41 (AB4, WN5h), the only known single Wolf-Rayet star in the SMC, are derived from ultraviolet (IUE), optical (AAT) and near-IR (NTT) spectroscopy. Contrary to expectations, the stellar properties of Sk41 are…

(Abridged) We have performed a comprehensive multiwavelength analysis of a sample of 20 starburst galaxies that show the presence of a substantial population of very young massive stars. In this paper, the second of the series, we present…

Massive evolved stars loss a large fraction of their mass via copious stellar wind or instant outbursts and during certain evolutionary phases they can be identified via the presence of their circumstellar nebulae. In this paper, we present…