Related papers: The clumpiness of Luminous Blue Variable winds
Luminous blue variables (LBVs) are evolved massive stars close to the Eddington limit, with a distinct spectroscopic and photometric variability having unsteady mass-loss rates. These stars show a considerable change in their surface…
The polarization of the Cosmic Microwave Background (CMB) is rich in information but obscured by foreground emission from the Milky Way's interstellar medium (ISM). To uncover relationships between the underlying turbulent ISM and the…
B supergiants (BSGs) are evolved stars with effective temperatures between 10 to 30 kK and are important to understand massive star evolution. Located on the edge of the line-driven wind regime, the study of their atmospheres is helpful to…
Polarimetric measurements, especially if extended at high energy, are expected to provide important insights into the mechanisms underlying the acceleration of relativistic particles in jets. In a previous work we have shown that the…
Planetary-scale waves at the Venusian cloud-top cause periodic variations in both winds and ultraviolet (UV) brightness. While the wave candidates are the 4-day Kelvin wave and 5-day Rossby wave with zonal wavenumber 1, their temporal…
We present the results of a systematic observational campaign designed to search for microvariability in the optical polarization of BL Lac objects. We have observed a sample formed by 8 X-ray-selected and 10 radio-selected sources, looking…
We report optical and near-infrared spectra of the central star of the radio source G79.29+0.46, a candidate luminous blue variable. The spectra contain numerous narrow (FWHM < 100 km/s emission lines of which the low-lying hydrogen lines…
Mass-loss rates currently in use for hot, massive stars have recently been seriously questioned, mainly because of the effects of wind clumping. We investigate the impact of clumping on diagnostic ultraviolet resonance and optical…
Previous studies have explained the shapes of LBV nebulae, such as eta Car, by invoking the interaction of an isotropic fast wind with a previously deposited, slow aspherical wind (a "slow torus"). In this work I focus on the opposite…
Polarized thermal emission from Galactic dust is the dominant foreground for CMB polarization measurements at high frequencies, with its statistical properties set by the interplay between turbulence and magnetic fields in the multiphase…
Luminous blue variables (LBVs) are expected to play an important role in massive stellar evolution as well as being the progenitors of some of the most luminous supernovae known. In this paper we provide a multiwavelength study of 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…
The influence of the wind to the total continuum of OB supergiants is discussed. For wind velocity distributions with \beta > 1.0, the wind can have strong influence to the total continuum emission, even at optical wavelengths. Comparing…
Winds of massive stars have density inhomogeneities (clumping) that may affect the formation of spectral lines in different ways, depending on their formation region. Most of previous and current spectroscopic analyses have been performed…
High-mass binaries hosting young pulsars can be powerful gamma-ray emitters. The stellar wind of the massive star in the system is expected to be clumpy. Since the high-energy emission comes from the pulsar-star wind interaction, the…
Aims: The X-ray emission of massive stars has been studied when these objects are in their main-sequence phase, as well as in their Wolf-Rayet phase. However, the X-ray properties of the transitional Luminous Blue Variable (LBV) phase…
We study the influence of clumping on the predicted wind structure of O-type stars. For this purpose we artificially include clumping into our stationary wind models. When the clumps are assumed to be optically thin, the radiative line…
Polarized emission from aligned dust is a crucial tool for studies of magnetism in the ISM and a troublesome contaminant for studies of CMB polarization. In each case, an understanding of the significance of the polarization signal requires…
In this work we present the spectrum modeling results for the newly discovered luminous blue variable (LBV) in the NGC 1156 galaxy. Extended atmosphere models were calculated using the non-LTE code CMFGEN. We have obtained the luminosity of…
A debate has arisen concerning the fundamental nature of LBVs) and their role in stellar evolution. While Smith and Tombleson proposed that their isolated environments indicate that LBVs must be largely the product of binary evolution,…