TY - CHAP A1 - Puls, Joachim A1 - Markova, N. A1 - Najarro, F. A1 - Hanson, M. M. T1 - Clumping in O-star winds N2 - We review various diagnostics of clumping in O-star winds, with special emphasis on its radial stratification. Implications and problems are discussed, and promising NIR methods are presented. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17683 ER - TY - CHAP A1 - Najarro, F. A1 - Puls, Joachim A1 - Herrero, A. A1 - Hanson, M. M. A1 - Martín-Pintado, J. A1 - Hillier, D. J. T1 - Tracking the Clumping in OB Stars from UV to radio N2 - We review different line and continua diagnostics from the UV to radio, which can be utilized to simultaneously constrain the clumping structure throughout the stellar wind of massive OB stars. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17701 ER - TY - GEN A1 - Vink, Jorick Sandor A1 - Heger, Alexander A1 - Krumholz, Mark R. A1 - Puls, Joachim A1 - Banerjee, Shiladitya A1 - Castro, Norberto A1 - Chen, K.-J. A1 - Chenè, A.-N. A1 - Crowther, P. A. A1 - Daminelli, A. A1 - Gräfener, G. A1 - Groh, J. H. A1 - Hamann, Wolf-Rainer A1 - Heap, S. A1 - Herrero, A. A1 - Kaper, L. A1 - Najarro, F. A1 - Oskinova, Lida A1 - Roman-Lopes, A. A1 - Rosen, A. A1 - Sander, A. A1 - Shirazi, M. A1 - Sugawara, Y. A1 - Tramper, F. A1 - Vanbeveren, D. A1 - Voss, R. A1 - Wofford, A. A1 - Zhang, Y. T1 - Very massive stars in the local universe T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 601 KW - stars: massive stars KW - stars: mass-loss KW - stars: stellar evolution Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-415220 SN - 1866-8372 IS - 601 ER - TY - JOUR A1 - Najarro, F. A1 - de la Fuente, D. A1 - Geballe, T. R. A1 - Figer, D. F. A1 - Hillier, D. J. T1 - The WR population in the Galactic Center JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - The Galactic Center (GC) hosts three of the most massive WR rich, resolved young clusters in the Local Group as well as a large number of apparently isolated massive stars. Therefore, it constitutes a test bed to study the star formation history of the region, to probe a possible top-heavy scenario and to address massive star formation (clusters vs isolation) in such a dense and harsh environment. We present results from our ongoing infrared spectroscopic studies of WRs and other massive stars at the Center of the Milky Way. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87794 SP - 113 EP - 116 ER - TY - JOUR A1 - Kourniotis, M. A1 - Bonanos, A. A1 - Najarro, F. T1 - Accurate parameters of massive binaries in the Danks clusters JF - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 N2 - We present results from our near-infrared spectroscopy with VLT/ISAAC of four, massive eclipsing binary systems in the young, heavily reddened, massive Danks clusters. We derive accurate fundamental parameters and the distance to these massive systems, which comprise of OIf+, WR and O-type stars. Our goal is to increase the sample of well-studied WR stars and constrain their physics by comparison with evolutionary models. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87819 SP - 121 EP - 124 ER -