The origin and impact of Wolf-Rayet-type mass loss

• Verfasst von: Sander, Andreas A. C. [VerfasserIn]
• Verfasst von: Vink, Jorick S. [VerfasserIn]
• Verfasst von: Higgins, Erin R. [VerfasserIn]
• Verfasst von: Shenar, Tomer [VerfasserIn]
• Verfasst von: Hamann, Wolf-Rainer [VerfasserIn]
• Verfasst von: Todt, Helge [VerfasserIn]
• Titel: The origin and impact of Wolf-Rayet-type mass loss
• Verf.angabe: Andreas A.C. Sander, Jorick S. Vink, Erin R. Higgins, Tomer Shenar, Wolf-Rainer Hamann and Helge Todt
• Jahr: 2020
• Umfang: 6 S.
• Illustrationen: Illustrationen
• Fussnoten: Elektronische Reproduktion der Druck-Ausgabe ; Gesehen am 08.07.2024
• Titel Quelle: Enthalten in: International Astronomical UnionProceedings of the International Astronomical Union
• Ort Quelle: Cambridge : Cambridge Univ. Press, 2004
• Jahr Quelle: 2020
• Band/Heft Quelle: 16(2020), S366, Seite 21-26
• ISSN Quelle: 1743-9221
• DOI: doi:10.1017/S1743921322000400
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: galaxies: stellar content
• Sach-SW: outflows
• Sach-SW: stars: atmospheres
• Sach-SW: stars: black holes
• Sach-SW: stars: evolution
• Sach-SW: stars: mass loss
• Sach-SW: stars: massive
• Sach-SW: stars: winds
• Sach-SW: stars: Wolf-Rayet
• K10plus-PPN: 1894528301
• K10plus-PPN:
  Universitätsbibliothek
• Lokale URL UB: Zum Volltext

Abstract

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.