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

  title={The Eddington factor as the key to understand the winds of the most massive stars. Evidence for a $\Gamma$-dependence of Wolf-Rayet type mass loss},
  author={Gotz Grafener and Jacco Vink and Alex de Koter and Norbert Langer},
  journal={Astronomy and Astrophysics},
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 strong mass loss. In previous theoretical studies this enhanced mass loss has been attributed to their proximity to the Eddington limit. Aims. We investigate observed trends in the mass-loss properties of such young, very massive stars to examine a potential Γ-dependence, i.e., with respect to 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
Stellar mass-loss near the Eddington limit Tracing the sub-photospheric layers of classical Wolf-Rayet stars
Context. Towards the end of their evolution, hot massive stars develop strong stellar winds and appear as emission line stars, such as Wolf-Rayet (WR) stars or luminous blue variables (LBVs). The
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
Mass loss and the Eddington parameter: a new mass-loss recipe for hot and massive stars
Mass loss through stellar winds plays a dominant role in the evolution of massive stars. In particular the mass-loss rates of very massive stars (VMSs, $> 100\,M_{\odot}$) are highly uncertain. Such
Very massive stars: a metallicity-dependent upper-mass limit, slow winds, and the self-enrichment of globular clusters
  • J. Vink
  • Physics
    Astronomy & Astrophysics
  • 2018
One of the key questions in Astrophysics concerns the issue of whether there exists an upper-mass limit to stars, and if so, what physical mechanism sets this limit? The answer to this question might
Physics and evolution of the most massive stars in 30 Doradus
The identification of stellar-mass black-hole mergers with up to 80 Msun as powerful sources of gravitational wave radiation led to increased interest in the physics of the most massive stars. The
The Wolf-Rayet stars in M 31. I. Analysis of the late-type WN stars
Context. Comprehensive studies of Wolf-Rayet stars were performed in the past for the Galactic and the LMC population. The results revealed significant differences, but also unexpected similarities
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
Massive main sequence stars evolving at the Eddington limit
The evolution of massive stars even on the main sequence is not yet well understood. Due to the steep mass-luminosity relation, massive main sequence stars become very luminous. This brings their
On the optically-thick winds of Wolf-Rayet stars
(abridged) The strong winds of Wolf-Rayet (WR) stars are important for the mechanical and chemical feedback of the most massive stars and determine whether they end their lives as neutron stars or


Mass loss from late-type WN stars and its Z-dependence: very massive stars approaching the Eddington limit
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
Are luminous and metal-rich Wolf-Rayet stars inflated?
Aims. We investigate the influence of metallicity and stellar wind mass loss on the radius of Wolf-Rayet stars. Methods. We have calculated chemically homogeneous models of Wolf-Rayet stars of 10 to
Metallicity in the Galactic Center: The Arches Cluster
We present a quantitative spectral analysis of five very massive stars in the Arches cluster, located near the Galactic center, to determine stellar parameters, stellar wind properties, and, most
Wind modelling of very massive stars up to 300 solar masses
The stellar upper-mass limit is highly uncertain. Some studies have claimed there is a universal upper limit of ∼150 M� . A factor that is often overlooked is that there might be a significant
The mass-loss rates of Wolf{Rayet stars explained by optically thick radiation driven wind models
Observed, clumping-corrected mass-loss rates of Galactic Wolf{Rayet (WR) stars are compared with predictions of the optically thick radiation driven wind models. We did not develop models for the
The most massive stars in the Arches cluster
Aims. We study a sample composed of 28 of the brightest stars in the Arches cluster. Our aim is to constrain their stellar and wind properties and to establish their nature and evolutionary status.
On the Evolutionary Phase and Mass Loss of the Wolf-Rayet-like Stars in R136a*
We report on a systematic study of the most massive stars, in which we analyzed the spectra of four very luminous stars in the Large Magellanic Cloud. The stars lie in the 30 Doradus complex, three
A consistent solution for the velocity field and mass-loss rate of massive stars
Stellar winds are an important aspect of our understanding of the evolution of massive stars and their input into the interstellar medium. Here we present solutions for the velocity field and
Evolution of rapidly rotating metal-poor massive stars towards gamma-ray bursts
Recent models of rotating massive stars including magnetic fields prove it difficult for the cores of single stars to retain enough angular momentum to produce a collapsar and gamma-ray burst. At low
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