Wolf-Rayet stars in the Small Magellanic Cloud: II. Analysis of the binaries

  title={Wolf-Rayet stars in the Small Magellanic Cloud: II. Analysis of the binaries},
  author={Tomer Shenar and Rainer Hainich and Helge Todt and Andreas A. C. Sander and W. R. Hamann and Anthony F. J. Moffat and J. J. Eldridge and Herbert Pablo and Lida M. Oskinova and Noel D. Richardson},
  journal={arXiv: Solar and Stellar Astrophysics},
Massive WR stars are evolved massive stars characterized by strong mass-loss. Hypothetically, they can form either as single stars or as mass donors in close binaries. About 40% of the known WR stars are confirmed binaries, raising the question as to the impact of binarity on the WR population. By performing a spectral analysis of all multiple WR systems in the SMC, we obtain the full set of stellar parameters for each individual component. Mass-luminosity relations are tested, and the… 
The Wolf–Rayet binaries of the nitrogen sequence in the Large Magellanic Cloud
Context. Massive Wolf–Rayet (WR) stars dominate the radiative and mechanical energy budget of galaxies and probe a critical phase in the evolution of massive stars prior to core collapse. It is not
Wolf-Rayet stars in the Small Magellanic Cloud as testbed for massive star evolution
The majority of Wolf-Rayet (WR) stars represent the stripped cores of evolved massive stars who lost most of their hydrogen envelope. In low metallicity environments, such as the Small Magellanic
The metallicity dependence of WR winds
Abstract Wolf-Rayet (WR) stars are the most advanced stage in the evolution of the most massive stars. The strong feedback provided by these objects and their subsequent supernova (SN) explosions are
Why binary interaction does not necessarily dominate the formation of Wolf-Rayet stars at low metallicity
Classical Wolf-Rayet (WR) stars are massive, hydrogen depleted, post main-sequence stars that exhibit emission-line dominated spectra. For a given metallicity Z, stars exceeding a certain initial
Low-metallicity massive single stars with rotation
Context. Metal-poor massive stars are assumed to be progenitors of certain supernovae, gamma-ray bursts, and compact object mergers that might contribute to the early epochs of the Universe with
Spectral models for binary products: Unifying subdwarfs and Wolf-Rayet stars as a sequence of stripped-envelope stars
Stars stripped of their hydrogen-rich envelope through interaction with a binary companion are generally not considered when accounting for ionizing radiation from stellar populations, despite the
A Study of Wolf-Rayet Stars Formed VIA Chemically Homogeneous Evolution
Abstract Using the stellar evolution code—Modules for Experiments in Stellar Astrophysics (MESA)—we investigate the evolution of massive stars with different rotational velocities and metallicities
The Galactic WC and WO stars
Wolf-Rayet stars of the carbon sequence (WC stars) are an important cornerstone in the late evolution of massive stars before their core collapse. As core-helium burning, hydrogen-free objects with
The Wolf–Rayet Content of the Galaxies of the Local Group and Beyond
Wolf–Rayet stars (WRs) represent the end of a massive star’s life as it is about to turn into a supernova. Obtaining complete samples of such stars across a large range of metallicities poses
Testing massive star evolution, star formation history, and feedback at low metallicity
Stars that start their lives with spectral types O and early B are the progenitors of core-collapse supernovae, long gamma-ray bursts, neutron stars, and black holes. These massive stars are the


Wolf-Rayet stars in the Small Magellanic Cloud: I. Analysis of the single WN stars
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
The Wolf-Rayet stars in the Large Magellanic Cloud - A comprehensive analysis of the WN class
Context. Massive stars, although being important building blocks of galaxies, are still not fully understood. This especially holds true for Wolf-Rayet (WR) stars with their strong mass loss, whose
Wolf-Rayet stars in the Magellanic Clouds. V: Binaries in the Small Magellanic cloud
Repeated spectroscopic observations of all eight W-R stars in the SMC are reported. Two of the stars are of the late, cool WN subclass, with one possibly an extreme Of star. One is definitely, the
Wolf—Rayet binaries in the Magellanic Clouds and implications for massive-star evolution — I. Small Magellanic Cloud
We have carried out an intensive spectroscopic campaign to search for binaries via periodic radial velocity (RV) variations among all the nitrogen-rich WN Wolf‐Rayet (WR) stars in the Small
The effect of massive binaries on stellar populations and supernova progenitors
We compare our latest single and binary stellar model results from the Cambridge stars code to several sets of observations. We examine four stellar population ratios: the number of blue to red
Stellar evolution with rotation XI. Wolf-Rayet star populations at different metallicities
Grids of models of massive stars (M ≥ 20 M� ) with rotation are computed for metallicities Z ranging from that of the Small Magellanic Cloud (SMC) to that of the Galactic Centre. The hydrostatic
The HD5980 multiple system: Masses and evolutionary status
New spectroscopic observations of the LBV/WR multiple system HD5980 in the Small Magellanic Cloud are used to address the question of the masses and evolutionary status of the two very luminous stars
The Wolf-Rayet Population Predicted by Massive Single Star and Massive Binary Evolution
We discuss the differences between massive single star and massive close binary population number synthesis predictions of WR stars. We show that the WC/WN number ratio as function of metallicity
Binary Interaction Dominates the Evolution of Massive Stars
More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases, greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations ofmassive stars and their supernovae.
The Eddington factor as the key to understand the winds of the most massive stars. Evidence for a Γ-dependence of Wolf-Rayet type mass loss
Context. The most massive stars are thought to be hydrogen-rich Wolf-Rayet stars of late spectral subtype (in the following WNh stars). The emission-line spectra of these stars are indicative of