@article{GeorgyEkstroemHirschietal.2015,
  author    = {Georgy, C. and Ekstr{\"o}m, S. and Hirschi, R. and Meynet, G. and Groh, J. H. and Eggenberger, P.},
  title     = {Wolf-Rayet stars as an evolved stage of stellar life},
  series = {Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.-5. June 2015},
  journal   = {Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.-5. June 2015},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-88097},
  pages     = {229 -- 232},
  year      = {2015},
  abstract  = {Wolf-Rayet (WR) stars, as they are advanced stages of the life of massive stars, provide a good test for various physical processes involved in the modelling of massive stars, such as rotation and mass loss. In this paper, we show the outputs of the latest grids of single massive stars computed with the Geneva stellar evolution code, and compare them with some observations. We present a short discussion on the shortcomings of single stars models and we also briefly discuss the impact of binarity on the WR populations.},
  language  = {en}
}
@article{Groh2015,
  author    = {Groh, J. H.},
  title     = {The end stages of massive star evolution},
  series = {Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.-5. June 2015},
  journal   = {Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.-5. June 2015},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-88115},
  pages     = {237 -- 240},
  year      = {2015},
  abstract  = {The morphological appearance of massive stars across their post-Main Sequence evolution and before the SN event is very uncertain, both from a theoretical and observational perspective. We recently developed coupled stellar evolution and atmospheric modeling of stars done with the Geneva and CMFGEN codes, for initial masses between 9 and 120 M⊙. We are able to predict the observables such as the high-resolution spectrum and broadband photometry. Here I discuss how the spectrum of a massive star changes across its evolution and before death, with focus on the WR stage. Our models indicate that single stars with initial masses larger than 30 M⊙ end their lives as WR stars. Depending on rotation, the spectrum of the star can either be that of a WN or WO subtype at the pre-SN stage. Our models allow, for the first time, direct comparison between predictions from stellar evolution models and observations of SN progenitors.},
  language  = {en}
}
@inproceedings{GrohHillierDamineli2007,
  author    = {Groh, J. H. and Hillier, D. J. and Damineli, A.},
  title     = {Mass-loss rate and clumping in LBV stars : the impact of time-dependent effects},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17773},
  year      = {2007},
  abstract  = {This paper outlines a newly-developed method to include the effects of time variability in the radiative transfer code CMFGEN. It is shown that the flow timescale is often large compared to the variability timescale of LBVs. Thus, time-dependent effects significantly change the velocity law and density structure of the wind, affecting the derivation of the mass-loss rate, volume filling factor, wind terminal velocity, and luminosity. The results of this work are directly applicable to all active LBVs in the Galaxy and in the LMC, such as AG Car, HR Car, S Dor and R 127, and could result in a revision of stellar and wind parameters. The massloss rate evolution of AG Car during the last 20 years is presented, highlighting the need for time-dependent models to correctly interpret the evolution of LBVs.},
  language  = {en}
}
@article{MeynetGeorgyMaederetal.2015,
  author    = {Meynet, G. and Georgy, C. and Maeder, A. and Ekstr{\"o}m, S. and Groh, J. H. and Barblan, F. and Song, H. F. and Eggenberger, P.},
  title     = {Physics of massive stars relevant for the modeling of Wolf-Rayet populations},
  series = {Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.-5. June 2015},
  journal   = {Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.-5. June 2015},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-87971},
  pages     = {183 -- 188},
  year      = {2015},
  abstract  = {Key physical ingredients governing the evolution of massive stars are mass losses, convection and mixing in radiative zones. These effects are important both in the frame of single and close binary evolution. The present paper addresses two points: 1) the differences between two families of rotating models, i.e. the family of models computed with and without an efficient transport of angular momentum in radiative zones; 2) The impact of the mass losses in single and in close binary models.},
  language  = {en}
}
@misc{VinkHegerKrumholzetal.2012,
  author    = {Vink, Jorick Sandor and Heger, Alexander and Krumholz, Mark R. and Puls, Joachim and Banerjee, Shiladitya and Castro, Norberto and Chen, K.-J. and Chen{\`e}, A.-N. and Crowther, P. A. and Daminelli, A. and Gr{\"a}fener, G. and Groh, J. H. and Hamann, Wolf-Rainer and Heap, S. and Herrero, A. and Kaper, L. and Najarro, F. and Oskinova, Lida and Roman-Lopes, A. and Rosen, A. and Sander, A. and Shirazi, M. and Sugawara, Y. and Tramper, F. and Vanbeveren, D. and Voss, R. and Wofford, A. and Zhang, Y.},
  title     = {Very massive stars in the local universe},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {601},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41522},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-415220},
  pages     = {29},
  year      = {2012},
  abstract  = {Recent studies have claimed the existence of very massive stars (VMS) up to 300 M⊙ in the local Universe. As this finding may represent a paradigm shift for the canonical stellar upper-mass limit of 150 M⊙, it is timely to discuss the status of the data, as well as the far-reaching implications of such objects. We held a Joint Discussion at the General Assembly in Beijing to discuss (i) the determination of the current masses of the most massive stars, (ii) the formation of VMS, (iii) their mass loss, and (iv) their evolution and final fate. The prime aim was to reach broad consensus between observers and theorists on how to identify and quantify the dominant physical processes.},
  language  = {en}
}