Related papers: New self-consistent wind parameters fitting optica…

We study stellar wind properties of selected late O stars in the Small Magellanic Cloud (SMC). We calculate NLTE line-driven wind models for these stars and compare predicted wind parameters with observed values. We found satisfactory…

We calculate NLTE line-driven wind models of selected O stars in the spectral range of O4 to O9 in the Small Magellanic Cloud (SMC). We compare predicted basic wind properties, i.e. the terminal velocity and the mass-loss rate with values…

We present a simple analysis of X-ray emission and absorption for hot-star winds, designed to explore the natural scalings of the observed X-ray luminosity with wind and sstellar properties. We show that an exospheric approximation, in…

Massive stars likely played an important role in the reionization of the Universe, and the formation of the first black holes. Massive stars in low-metallicity environments in the local Universe are reminiscent of their high redshift…

Analyzing the spectra from Wolf-Rayet stars requires adequate non-LTE modeling of their expanding atmosphere. The numerical schemes for solving the radiative transfer in the co-moving frame of reference have been developed by Mihalas and…

We present HST/STIS Ultraviolet spectra of the six known Ofpe/WN9 stars (``slash stars'') in M33. These stars were selected for showing the characteristics of the Ofpe/WN9 class from previous optical ground-based spectroscopy. The UV…

We present new computations of the ionizing spectral energy distributions (SEDs) and Lyman continuum (Lyc) and HeI continuum photon emission rates, for hot O-type and early B-type stars. We consider solar metallicity stars, with effective…

In this work, we select the high signal-to-noise ratio spectra of stars from the LAMOST data andmap theirMK classes to the spectral features. The equivalentwidths of the prominent spectral lines, playing the similar role as the multi-color…

This paper presents simulations of the metastable helium (He*) observations of WASP-107b, so far the highest signal-to-noise ratio detection that is confirmed by three different instruments. We employ full 3D hydrodynamics coupled with…

Mass-loss from massive stars is fundamental to stellar and galactic evolution and enrichment of the interstellar medium. Reliable determination of mass-loss rate is dependent upon unravelling details of massive star outflows, including…

Fast line-driven stellar winds play an important role in the evolution of planetary nebulae. We provide global hot star wind models of central stars of planetary nebulae. The models predict wind structure including the mass-loss rates,…

Recent spectropolarimetric surveys (MiMeS, BOB) have revealed that approximately 7% of massive stars host stable, surface dipolar magnetic fields with strengths on the order of kG. These fields channel the dense radiatively driven stellar…

We present a comprehensive grid of synthetic stellar-atmosphere spectra, suitable for the analysis of high resolution spectra of hydrogen-deficient post-Asymptotic Giant Branch (post-AGB) objects hotter than 50000 K, migrating along the…

We investigate the line-profile variability (lpv) of H-alpha for a large sample of O-type supergiants. We used the Temporal Variance Spectrum (TVS) analysis, developed by Fullerton et al 1996 and modified by us to take into account the…

We present some of the salient aspects of the scientific motivation for high resolution soft X-ray spectroscopy of early-type stars with the Line Emission Mapper X-ray Probe. The major strength of {\it LEM} for hot star physics is its large…

Context. Synthetic model atmosphere calculations are still the most commonly used tool when determining precise stellar parameters and stellar chemical compositions. Besides three-dimensional models that consistently solve for hydrodynamic…

We use a combination of VJHK and Spitzer} [3.6], [5.8] and [8.0] photometry, to determine IR excesses in a sample of LMC and SMC O stars. This sample is ideal for determining excesses because: 1) the distances to the stars, and hence their…

We review recent developments in determining the evolution of magnetic massive OB stars. One of the important scientific questions is the completeness and the detection limits of contemporaneous spectropolarimetric surveys across the HR…

Some studies have claimed a universal stellar upper-mass limit of 150 Msun. A factor that is often overlooked is that there might be a difference between the current and initial masses of the most massive stars, as a result of mass loss. We…

The discrepancies between theoretical and observed spectra, and the systematic differences between various spectroscopic parameter estimates, complicate the determination of atmospheric parameters of M-type stars. In this work, we present…