Related papers: iPTF14hls as a variable hyper-wind from a very mas…
By extending our self-consistent MHD simulations for the solar wind, we study the evolution of stellar winds of solar-type stars from early main sequence stage to red giant phase. Young solar-type stars are active and the mass loss rates…
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…
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 stellar winds and extremely high ionising…
Observations of normal galactic star-forming regions suggest there is widespread near-uniformity in the initial stellar mass function (IMF) in spite of diverse physical conditions. Fluctuations may come largely from statistical effects and…
A star that wanders too close to a massive black hole (BH) is shredded by the BH's tidal gravity. Stellar gas falls back to the BH, releasing a flare of energy. In anticipation of upcoming transient surveys, we predict the light curves and…
We report the outbursting source PTF 14jg, which prior to the onset of its late 2013 eruption, was a faint, unstudied, and virtually uncatalogued star. The salient features of the PTF 14jg outburst are: (i) projected location near the W4…
Planetary Nebulae (PN) emit enormous amount of energy in several emission lines. Measuring the line-flux for PNe in a given stellar population, the Planetary Nebula Luminosity Function (PNLF) can be compiled. Surveys of PNe revealed that…
It has been shown recently that the dynamical V-band mass-to-light ratios of compact stellar systems with masses from 10^6 to 10^8 Solar masses are not consistent with the predictions from simple stellar population (SSP) models. Top-heavy…
Type Ic supernovae (SNe Ic) arise from the core-collapse of H (and He) poor stars, which could be either single WR stars or lower-mass stars stripped of their envelope by a companion. Their light curves are radioactively powered and usually…
Mass loss from massive stars located in the part of the Hertzsprung-Russell diagram (HRD) where we find luminous blue variables (LBVs) is profoundly important for stellar evolution yet poorly understood. We use time-dependent…
Over the last years a new generation of model atmosphere codes, which include the effects of metal line-blanketing of millions of spectral lines in NLTE, has been used to re-determine the properties of massive stars through quantitative…
SN 2014C was originally classified as a Type Ib supernova, but at phase {\phi} = 127 d post-explosion strong H{\alpha} emission was observed. SN 2014C has since been observed in radio, infrared, optical and X-ray bands. Here we present new…
We introduce the first synthetic light-curve model set of Type IIP supernovae exploded within circumstellar media in which the acceleration of the red supergiant winds is taken into account. Because wind acceleration makes the wind…
We present late-time (590-994 d) mid-IR photometry of the normal, but highly-reddened Type IIP supernova SN 2002hh. Bright, cool, slowly-fading emission is detected from the direction of the supernova. Most of this flux appears not to be…
Observations and theories of the stellar initial mass function are reviewed. The universality and large total mass range of the power law portion of the IMF suggest a connection between stellar mass and cloud structure. The fractal patterns…
We suggest that the mass lost during the evolution of very massive stars may be dominated by optically thick, continuum-driven outbursts or explosions, instead of by steady line-driven winds. In order for a massive star to become a WR star,…
Type IIP supernova progenitors are often surrounded by dense circumstellar media that may result from mass-loss enhancement of the progenitors shortly before their explosions. Previous light-curve studies suggest that the mass-loss rates…
The classical model for free-free emission from ionized stellar winds is based on the assumption of a stationary, isotropic and homogeneous wind. However, since there exist objects whose wind behaviour deviates from the standard model,…
Intermediate-mass stars end their lives by ejecting the bulk of their envelope via a slow dense wind back into the interstellar medium, to form the next generation of stars and planets. Stellar pulsations are thought to elevate gas to an…
Spectra and phototometry of type IIn supernova SN 1997eg are used to determine properties of the circumstellar gas lost by the presupernova during the latest 200 years before the explosion. The analysis of narrow H$\alpha$ and [Fe X] 6374…