The origin and impact of Wolf-Rayet-type mass loss
Classical Wolf-Rayet (WR) stars mark an important stage in the late evolution of massive stars. As hydrogen-poor massive stars, these objects have lost their outer layers, while still losing further mass through strong winds indicated by their prominent emission line spectra. Wolf-Rayet stars have b...
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| Main Authors: | , , , , , |
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| Format: | Article (Journal) Conference Paper |
| Language: | English |
| Published: |
2020
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| In: |
Proceedings of the International Astronomical Union
Year: 2020, Volume: 16, Issue: S366, Pages: 21-26 |
| ISSN: | 1743-9221 |
| DOI: | 10.1017/S1743921322000400 |
| Online Access: | Verlag, kostenfrei, Volltext: https://doi.org/10.1017/S1743921322000400 Verlag, kostenfrei, Volltext: https://www.cambridge.org/core/journals/proceedings-of-the-international-astronomical-union/article/origin-and-impact-of-wolfrayettype-mass-loss/3EB0F84F75DBA200EE15ABEB9026338C 
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| Author Notes: | Andreas A.C. Sander, Jorick S. Vink, Erin R. Higgins, Tomer Shenar, Wolf-Rainer Hamann and Helge Todt |
| Summary: | Classical Wolf-Rayet (WR) stars mark an important stage in the late evolution of massive stars. As hydrogen-poor massive stars, these objects have lost their outer layers, while still losing further mass through strong winds indicated by their prominent emission line spectra. Wolf-Rayet stars have been detected in a variety of different galaxies. Their strong winds are a major ingredient of stellar evolution and population synthesis models. Yet, a coherent theoretical picture of their strong mass-loss is only starting to emerge. In particular, the occurrence of WR stars as a function of metallicity (Z) is still far from being understood. - To uncover the nature of the complex and dense winds of Wolf-Rayet stars, we employ a new generation of model atmospheres including a consistent solution of the wind hydrodynamics in an expanding non-LTE situation. With this technique, we can dissect the ingredients driving the wind and predict the resulting mass-loss for hydrogen-depleted massive stars. Our modelling efforts reveal a complex picture with strong, non-linear dependencies on the luminosity-to-mass ratio and Z with a steep, but not totally abrupt onset for WR-type winds in helium stars. With our findings, we provide a theoretical motivation for a population of helium stars at low Z, which cannot be detected via WR-type spectral features. Our study of massive He-star atmosphere models yields the very first mass-loss recipe derived from first principles in this regime. Implementing our first findings in stellar evolution models, we demonstrate how traditional approaches tend to overpredict WR-type mass loss in the young Universe. |
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| Item Description: | Elektronische Reproduktion der Druck-Ausgabe Gesehen am 08.07.2024 |
| Physical Description: | Online Resource |
| ISSN: | 1743-9221 |
| DOI: | 10.1017/S1743921322000400 |