ﻻ يوجد ملخص باللغة العربية
We investigate the ionization structure in the non-spherical winds and disks of B[e] stars. Especially the luminous B[e] supergiants seem to have outflowing disks which are neutral in hydrogen already close to the stellar surface. The existence of neutral material so close to the central star is surprising and needs to be investigated in detail. We perform our model calculations mainly in the equatorial plane, trying to find a plausible scenario that leads to recombination in the vicinity of the hot stars. Two different approaches are presented that both result in a hydrogen neutral equatorial region. We especially focus on the influence of stellar rotation which is known to play a significant role in shaping non-spherical winds. We show that a rotating star can have a neutral equatorial wind, even without the need of a density enhancement due to bi-stability or wind compression, but simply due to graviational darkening in combination with the known high mass-loss rates of the B[e] stars and especially the B[e] supergiants.
We are investigating the circumstellar material for a sample of B[e] stars using high spectral resolution data taken in the optical and near-infrared regions with ESO/FEROS and ESO/CRIRES spectrographs, respectively. B[e] stars are surrounded by dens
The effects of rapid rotation and bi--stability upon the density contrast between the equatorial and polar directions of a B[e] supergiant are investigated. Based on a new slow solution for different high rotational radiation--driven winds and the fa
In order to compare the x-wind with observations, one needs to be able to calculate its thermal and ionization properties. We formulate the physical basis for the streamline-by-streamline integration of the ionization and heat equations of the steady
We investigate the possible role of line-driven winds in the circumstellar envelope in B[e] stars, mainly the role of the $Omega$-slow wind solution, which is characterized by a slower terminal velocity and higher mass-loss rate, in comparison with t
B[e] Supergiants are a phase in the evolution of some massive stars for which we have observational evidence but no predictions by any stellar evolution model. The mass-loss during this phase creates a complex circumstellar environment with atomic, m