Stellar mass-loss near the Eddington limit Tracing the sub-photospheric layers of classical Wolf-Rayet stars

  title={Stellar mass-loss near the Eddington limit Tracing the sub-photospheric layers of classical Wolf-Rayet stars},
  author={Gotz Grafener and Jorick S. Vink},
  journal={Astronomy and Astrophysics},
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 quantitative description of the mass loss in these important presupernova phases is hampered by unknowns, such as clumping and porosity due to an inhomogeneous wind structure and by an incomplete theoretical understanding of optically thick stellar winds. Even the stellar radii in these phases are… 
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
Hydrostatic models of Wolf-Rayet stars typically contain low-density outer envelopes that inflate the stellar radii by a factor of several and are capped by a denser shell of gas. Inflated envelopes
Diagnostics of the unstable envelopes of Wolf-Rayet stars
Context. The envelopes of stars near the Eddington limit are prone to various instabilities. A high Eddington factor in connection with the iron opacity peak leads to convective instability, and a
Helium Star Models with Optically Thick Winds: Implications for the Internal Structures and Mass-loss Rates of Wolf–Rayet Stars
We construct helium (He) star models with optically thick winds and compare them with the properties of Galactic Wolf–Rayet (WR) stars. Hydrostatic He-core solutions are connected smoothly to
The Wolf–Rayet Stellar Response To The Iron Opacity Bump: Envelope Inflation, Winds, and Microturbulence
  • S. Ro
  • Physics
    The Astrophysical Journal
  • 2019
Early-type Wolf–Rayet (WR) stellar models harbor a super-Eddington layer in their outer envelopes due to a prominent iron opacity bump. In the past few decades, one-dimensional hydrostatic and
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
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 VLT-FLAMES Tarantula Survey XVII. Physical and wind properties of massive stars at the top of the main sequence
The evolution and fate of very massive stars (VMS) is tightly connected to their mass-loss properties. Their initial and final masses differ significantly as a result of mass loss. VMS have strong
Massive stars on the verge of exploding: the properties of oxygen sequence Wolf-Rayet stars
Context. Oxygen sequence Wolf-Rayet (WO) stars represent a very rare stage in the evolution of massive stars. Their spectra show strong emission lines of helium-burning products, in particular highly
A massive white-dwarf merger product before final collapse
The observations indicate that super-Chandrasekhar-mass white-dwarf mergers can avoid thermonuclear explosion as type Ia supernovae, and provide evidence of the generation of magnetic fields in stellar mergers.


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
Stellar envelope inflation near the Eddington limit - Implications for the radii of Wolf-Rayet stars and luminous blue variables
Context. It has been proposed that the envelopes of luminous stars may be subject to substantial radius inflation. The peculiar structure of such inflated envelopes, with an almost void, radiatively
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 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
Mass loss from inhomogeneous hot star winds - I. Resonance line formation in 2D models
Context. The mass-loss rate is a key parameter of hot, massive stars. Small-scale inhomogeneities (clumping) in the winds of these stars are conventionally included in spectral analyses by assuming
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
Stellar and wind properties of LMC WC4 stars A metallicity dependence for Wolf-Rayet mass-loss rates ?
We use ultraviolet space-based (FUSE, HST) and optical/IR ground-based (2.3 m MSSSO, NTT) spectroscopy to determine the physical parameters of six WC4-type Wolf-Rayet stars in the Large Magellanic
Neglecting the porosity of hot-star winds can lead to underestimating mass-loss rates
Context. The mass-loss rate is a key parameter of massive stars. Adequate stellar atmosphere models are required for spectral analyses and mass-loss determinations. Present models can only account
Mass loss from inhomogeneous hot star winds - II. Constraints from a combined optical/UV study
Context. Mass loss is essential for massive star evolution, thus also for the variety of astrophysical applications relying on it s predictions. However, mass-loss rates currently in use for hot,
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.