Related papers: Wolf-Rayet Mass-Loss Limits Due to Frequency Redis…
Stellar winds are one of the most important drivers of massive star evolution and a vital source of chemical, mechanical, and radiative feedback. Despite its significance, mass loss remains a major uncertainty in stellar evolution models.…
Binary mass transfer via Roche-lobe overflow (RLOF) is a key channel for producing stripped-envelope Wolf-Rayet (WR) stars and may be critical to account for SN Ib/c progenitors. RY Scuti is an extremely rare example of a massive binary…
One of the main properties of Wolf-Rayet (WR) stars is a very intense outflow of gas. No less than 40\% \ of WR stars belong to binary systems. Young massive O and B stars are the secondary components of such systems. OB stars also have an…
Cygnus X-3, hosting a Wolf-Rayet (WR) star whose dense wind produces various spectral lines due to photoionization by X-rays from a compact object, provides an ideal laboratory for studying wind dynamics and density structure. We measured…
We investigate the influence of Wolf-Rayet (W-R) stars on their surrounding star-forming molecular clouds. We study five regions containing W-R stars in the inner Galactic plane ($l\sim$[14$^\circ$-52$^\circ$]), using multi-wavelength data…
The high-ionization lines of the broad-line region (BLR) of thermal active galactic nuclei (AGNs) show blueshifts of a few hundred km/s to several thousand km/sec with respect to the low-ionization lines. This has long been thought to be…
Second only to initial mass, the rate of wind-driven mass loss determines the final mass of a massive star and the nature of its remnant. Motivated by the need to reconcile observational values and theory, we use a recently vetted technique…
We present modeling research work of the winds and circumstellar environments of prototypical hot and cool massive stars using advanced radiative transfer (RT) calculations. This research aims at unraveling the detailed physics of various…
Wolf-Rayet (WR) stars are evolved massive stars with strong fast stellar winds. WR stars in our Galaxy have shown three possible sources of X-ray emission associated with their winds: shocks in the winds, colliding stellar winds, and…
Oxygen sequence Wolf-Rayet stars (WO) are thought to be the final evolution phase of some high mass stars, as such they may be the progenitors of type Ic SNe as well as potential progenitors of broad-lined Ic and long gamma-ray bursts. We…
Many Wolf-Rayet (WR) stars have optically thick winds that cloak the hydrostatic layers of the underlying star. In these cases, traditional spectral analysis methods are plagued by degeneracies that make it difficult to constrain parameters…
Photoevaporative winds are a promising mechanism for dispersing protoplanetary discs, but so far theoretical models have been unable to agree on the relative roles that the X-ray, Extreme Ultraviolet or Far Ultraviolet play in driving the…
[Abridged] We present a comprehensive study of the metallicity dependence of the mass-loss rates in stationary stellar winds of hot massive stars. Assuming a power-law dependence of mass loss on metallicity, Mdot \propto Z^{m}, and adopting…
We use a combination of radiation hydrodynamics (rad-HD) and photoionization modeling to study line-driven disc winds for a range of black hole masses. We refined previous models by incorporating heating, cooling, and radiation forces from…
Fine-structure mid-infrared emission lines with critical densities in the regime 10^4 to 10^6 cm^-3 can be employed to probe the outflow from Wolf-Rayet stars at radii of \sim 10^15 cm. Narrow-band mid-infrared imaging and spectroscopy of…
Stellar winds of cool carbon stars enrich the interstellar medium with significant amounts of carbon and dust. We present a study of the influence of two-fluid flow on winds where we add descriptions of frequency-dependent radiative…
We present a simple analytical method to describe the structure of a spherically expanding envelope with strong mass outflow. The structure is consistently connected to the hydrostatic stellar interior and provides an adequate description…
We present mid-infrared spectra of the microquasar SS 433 obtained with the Infrared Space Observatory (spectroscopic mode of ISOPHOT) and compare them to the spectra of four Wolf-Rayet stars. The mid-infrared spectrum of SS 433 shows…
We present a spectroscopic analysis of VLT/X-Shooter observations of six O-type stars in the low-metallicity (Z ~ 1/7 Z\odot) galaxies IC 1613, WLM and NGC 3109. The stellar and wind parameters of these sources allow us, for the first time,…
Numerical simulations of the evolution of strange-mode instabilities into the non-linear regime have been performed for a wide range of stellar parameters for Wolf-Rayet stars. It has been shown that the Wolf-Rayet models reach radial…