Related papers: Subsonic structure and optically thick winds from …

We use radiation-hydrodynamical simulations to investigate the formation and synthetic X-ray emission of hot bubbles within planetary nebulae (PNe) driven by the powerful winds of H-deficient, [Wolf-Rayet]([WR])-type stars. Our models,…

Current mass-loss rate estimates imply that main sequence winds are not sufficient to strip away the H-rich envelope to yield Wolf-Rayet (WR) stars. The rich transitional population of Westerlund 1 (Wd 1) provides an ideal laboratory to…

We report a multi-wavelength study of the Wolf Rayet (WR) star: [KSF2015] 1381-19L, which is located in the solar metallicity region (Z=0.014) of the Milky Way Galaxy, strongly obscured by the interstellar dust. We perform a detailed…

Stripped-envelope stars can be observed as Wolf-Rayet (WR) stars, or as less luminous hydrogen-poor stars with low mass loss rates and transparent winds. Both types are potential progenitors of Type I core-collapse supernovae (SNe). We use…

Wolf-Rayet (WR) stars are the evolutionary phases of very massive stars prior to the final supernova explosion stage. These stars lose substantial mass during WN and WC stages. The mass losses are associated with diverse elemental and…

In this contribution I summarize our current knowledge of the nature and significance of starburst-driven galactic winds (``superwinds''). Superwinds are complex multiphase outflows of cool, warm, and hot gas, dust, and magnetized…

A number of strong infrared forbidden lines have been observed in several evolved Wolf-Rayet star winds, and these are important for deriving metal abundances and testing stellar evolution models. In addition, because these optically thin…

We review our current understanding on the outer envelope structures of massive stars based on three dimensional (3D) radiation hydrodynamic simulations. We briefly summarize the fundamental issues to construct hydrostatic one dimensional…

We analyze the physical conditions in the low-ionization component of starburst outflows (in contrast to the high-ionization wind fluid observed in X-rays), based on new Keck/LRIS spectroscopy of partially resolved absorption troughs in…

Context. Radiation-driven mass loss is key to our understanding of massive-star evolution. However, for low-luminosity O-type stars there are big discrepancies between theoretically predicted and empirically derived mass-loss rates (called…

Galactic-scale outflows regulate the stellar mass growth and chemical enrichment of galaxies, yet key outflow properties such as the chemical composition and mass loss rate remain largely unknown. We address these properties with Keck/ESI…

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…

Massive stars deeply influence their surroundings by their luminosity and the injection of kinetic energy. So far, they have mostly been studied with spatially unresolved observations, although evidence of geometrical complexity of their…

Star formation is ubiquitously associated with the ejection of accretion-powered outflows that carve bipolar cavities through the infalling envelope. This feedback is expected to be important for regulating the efficiency of star formation…

The Small Magellanic Cloud (SMC) is the nearest low-metallicity dwarf galaxy. Its proximity and low reddening has enabled us to detect its Wolf-Rayet (WR) star population with 12 known objects. Quantitative spectroscopy of the stars…

Massive stars produce strong stellar winds that consist of continuous outflows of material at speeds of thousands of km/s. These winds convey large amounts of kinetic power, especially in the case of Wolf-Rayet (WR) stars. When these winds…

We present refined color-color selection criteria for identifying Wolf-Rayet (WR) stars using available mid infrared (MIR) photometry from WISE in combination with near infrared (NIR) photometry from 2MASS. Using a sample of spectrally…

Massive, luminous stars reaching the Eddington limit in their interiors develop very dilute, extended envelopes. This effect is called envelope inflation. If the progenitors of Type Ib/c supernovae, which are believed to be Wolf-Rayet (WR)…

Measurements of interstellar absorption lines in 18 ultraluminous infrared galaxies (ULIGs) have been combined with published data, in order to reassess the dependence of galactic outflow speeds on starburst luminosity and galactic mass.…

Winds arising from galaxies, star clusters, and active galactic nuclei are crucial players in star and galaxy formation, but it has proven remarkably difficult to use observations of them to determine physical properties of interest,…