منابع مشابه
Stellar wind bubbles around WR and [WR] stars
We study the dynamics of stellar wind bubbles around hydrogen-deficient stars using numerical simulations with timeand ion dependent cooling. We consider two types of hydrogen-deficient stars, massive WR stars, producing Ring Nebulae, and low mass [WR] stars, producing Planetary Nebulae. We show that for the Planetary Nebulae, the different cooling properties of the hydrogen-deficient wind lead...
متن کاملLong - term photometry of the Wolf - Rayet stars WR 137 , WR 140 , WR 148 , and WR 153 ⋆
In 1991, a long term UBV -photometry campaign of four Wolf-Rayet stars was started using the 60 cm telescope of the National Astronomical Observatory Rozhen, Bulgaria. Here we report on our observational results and discuss the light variations. The star WR137 was observed during 1991 1998. No indications of eclipses were found, though random light variations with small amplitudes exist, which ...
متن کاملDetection of WR stars in the metal – poor starburst galaxy
Wolf-Rayet stars (WR) have been detected in the NW region of the metal–poor starburst galaxy IZw 18. The integrated luminosity and FWHM of the bumps at 4650Å and 5808Å are consistent with the presence of a few individual stars of WC4 or WC5 type. Evolutionary synthesis models predict few WRs in this galaxy, but only of WN type. The presence of WC stars at such low metallicity could however be e...
متن کاملShaping Planetary Nebulae: Is It Different for [wr] Stars?
The Wolf–Rayet phenomenon is a stellar phenomenon. This means that its length scale is essentially that of the star, i.e. some 10 cm. A typical nebular size is 10 cm or higher, which immediately illustrates that it may not be easy to make the connection between the star and the nebulae and observations confirm this. In this paper I will try to discuss some ways in which the nebular properties c...
متن کاملProgress in Model Atmosphere Studies of WR stars
Recent progress in the quantitative analysis of Wolf-Rayet stars is reviewed, emphasising the role played by choice of spectral diagnostics, clumping and line blanketing on derived stellar properties. The ionizing properties of WR stars are discussed, based on clumped, line blanketed models for WN and WC stars. The role of metallicity and mass-loss is assessed, and the role of H ii regions as p...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 2003
ISSN: 0074-1809
DOI: 10.1017/s0074180900208516