High Resolution X-Ray Spectra of WR 6

  • As WR 6 is a putatively single WN4 star, and is relatively bright (V = 6.9), it is an ideal case for studying the wind mechanisms in these extremely luminous stars. To obtain higher resolution spectra at higher energy (above 1 keV) than previously obtained with the XMM/Newton RGS, we have observed WR 6 with the Chandra High Energy Transmission Grating Spectrometer for 450 ks. We have resolved emission lines of S, Si, Mg, Ne, and Fe, which all show a “fin"-shaped prole, characteristic of a self-absorbed uniformly expanding shell. Steep blue edges gives robust maximal expansion velocities of about 2000 km/s, somewhat larger than the 1700km/s derived from UV lines. The He-like lines all indicate that X-ray emitting plasmas are far from the photosphere – even at the higher energies where opacity is lowest { as was also the case for the longer wavelength lines observed with XMM-Newton/RGS. Abundances determined from X-ray spectral modeling indicate enhancements consistent with nucleosynthesis. The star was also variable in X-rays and inAs WR 6 is a putatively single WN4 star, and is relatively bright (V = 6.9), it is an ideal case for studying the wind mechanisms in these extremely luminous stars. To obtain higher resolution spectra at higher energy (above 1 keV) than previously obtained with the XMM/Newton RGS, we have observed WR 6 with the Chandra High Energy Transmission Grating Spectrometer for 450 ks. We have resolved emission lines of S, Si, Mg, Ne, and Fe, which all show a “fin"-shaped prole, characteristic of a self-absorbed uniformly expanding shell. Steep blue edges gives robust maximal expansion velocities of about 2000 km/s, somewhat larger than the 1700km/s derived from UV lines. The He-like lines all indicate that X-ray emitting plasmas are far from the photosphere – even at the higher energies where opacity is lowest { as was also the case for the longer wavelength lines observed with XMM-Newton/RGS. Abundances determined from X-ray spectral modeling indicate enhancements consistent with nucleosynthesis. The star was also variable in X-rays and in simultaneous optical photometry obtained with Chandra aspect camera, but not coherently with the optically known period of 3.765 days.show moreshow less

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Metadaten
Author:D. Huenemoerder, K. Gayley, Wolf-Rainer HamannORCiDGND, R. Ignace, J. Nichols, L. M. Oskinova, A. M. T. Pollock, N. Schulz
URN:urn:nbn:de:kobv:517-opus4-88236
Parent Title (English):Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015
Document Type:Article
Language:English
Year of Completion:2015
Publishing Institution:Universität Potsdam
Release Date:2016/02/23
First Page:301
Last Page:304
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften
Publication Way:Universitätsverlag Potsdam
Collections:Universität Potsdam / Tagungsbände/Proceedings (nicht forlaufend) / Wolf-Rayet Stars: Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 / Wolf-Rainer Hamann, Andreas Sander, Helge Todt (Eds.)
Universität Potsdam / Tagungsbände/Proceedings (nicht forlaufend) / Wolf-Rayet Stars: Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015 / Wolf-Rainer Hamann, Andreas Sander, Helge Todt (Eds.) / X-rays and WR stars
Licence (German):License LogoKeine Nutzungslizenz vergeben - es gilt das deutsche Urheberrecht