HIGH-RESOLUTION X-RAY SPECTROSCOPY REVEALS THE SPECIAL NATURE OF WOLF-RAYET STAR WINDS
We present the first high-resolution X-ray spectrum of a putatively single Wolf-Rayet (WR) star. 400 ks observations of WR 6 by the XMM-Newton telescope resulted in a superb quality high-resolution X-ray spectrum. Spectral analysis reveals that the X-rays originate far out in the stellar wind, more...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2015
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| Online Access: | http://hdl.handle.net/1721.1/95464 |
| _version_ | 1826200448554500096 |
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| author | Oskinova, Lidia M. Gayley, K. G. Hamann, W.-R. Ignace, R. Pollock, A. M. T. Huenemoerder, David P. |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Oskinova, Lidia M. Gayley, K. G. Hamann, W.-R. Ignace, R. Pollock, A. M. T. Huenemoerder, David P. |
| author_sort | Oskinova, Lidia M. |
| collection | MIT |
| description | We present the first high-resolution X-ray spectrum of a putatively single Wolf-Rayet (WR) star. 400 ks observations of WR 6 by the XMM-Newton telescope resulted in a superb quality high-resolution X-ray spectrum. Spectral analysis reveals that the X-rays originate far out in the stellar wind, more than 30 stellar radii from the photosphere, and thus outside the wind acceleration zone where the line-driving instability (LDI) could create shocks. The X-ray emitting plasma reaches temperatures up to 50 MK and is embedded within the unshocked, "cool" stellar wind as revealed by characteristic spectral signatures. We detect a fluorescent Fe line at ≈6.4 keV. The presence of fluorescence is consistent with a two-component medium, where the cool wind is permeated with the hot X-ray emitting plasma. The wind must have a very porous structure to allow the observed amount of X-rays to escape. We find that neither the LDI nor any alternative binary scenario can explain the data. We suggest a scenario where X-rays are produced when the fast wind rams into slow "sticky clumps" that resist acceleration. Our new data show that the X-rays in single WR star are generated by some special mechanism different from the one operating in the O-star winds. |
| first_indexed | 2024-09-23T11:36:38Z |
| format | Article |
| id | mit-1721.1/95464 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T11:36:38Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/954642022-09-27T20:41:29Z HIGH-RESOLUTION X-RAY SPECTROSCOPY REVEALS THE SPECIAL NATURE OF WOLF-RAYET STAR WINDS Oskinova, Lidia M. Gayley, K. G. Hamann, W.-R. Ignace, R. Pollock, A. M. T. Huenemoerder, David P. MIT Kavli Institute for Astrophysics and Space Research Huenemoerder, David P. We present the first high-resolution X-ray spectrum of a putatively single Wolf-Rayet (WR) star. 400 ks observations of WR 6 by the XMM-Newton telescope resulted in a superb quality high-resolution X-ray spectrum. Spectral analysis reveals that the X-rays originate far out in the stellar wind, more than 30 stellar radii from the photosphere, and thus outside the wind acceleration zone where the line-driving instability (LDI) could create shocks. The X-ray emitting plasma reaches temperatures up to 50 MK and is embedded within the unshocked, "cool" stellar wind as revealed by characteristic spectral signatures. We detect a fluorescent Fe line at ≈6.4 keV. The presence of fluorescence is consistent with a two-component medium, where the cool wind is permeated with the hot X-ray emitting plasma. The wind must have a very porous structure to allow the observed amount of X-rays to escape. We find that neither the LDI nor any alternative binary scenario can explain the data. We suggest a scenario where X-rays are produced when the fast wind rams into slow "sticky clumps" that resist acceleration. Our new data show that the X-rays in single WR star are generated by some special mechanism different from the one operating in the O-star winds. United States. National Aeronautics and Space Administration (Grant SV3-73016) 2015-02-20T19:13:29Z 2015-02-20T19:13:29Z 2012-02 2012-01 Article http://purl.org/eprint/type/JournalArticle 2041-8205 2041-8213 http://hdl.handle.net/1721.1/95464 Oskinova, L. M., K. G. Gayley, W.-R. Hamann, D. P. Huenemoerder, R. Ignace, and A. M. T. Pollock. “HIGH-RESOLUTION X-RAY SPECTROSCOPY REVEALS THE SPECIAL NATURE OF WOLF-RAYET STAR WINDS.” The Astrophysical Journal 747, no. 2 (February 21, 2012): L25. © 2012 The American Astronomical Society en_US http://dx.doi.org/10.1088/2041-8205/747/2/l25 The Astrophysical Journal. Letters Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf IOP Publishing American Astronomical Society |
| spellingShingle | Oskinova, Lidia M. Gayley, K. G. Hamann, W.-R. Ignace, R. Pollock, A. M. T. Huenemoerder, David P. HIGH-RESOLUTION X-RAY SPECTROSCOPY REVEALS THE SPECIAL NATURE OF WOLF-RAYET STAR WINDS |
| title | HIGH-RESOLUTION X-RAY SPECTROSCOPY REVEALS THE SPECIAL NATURE OF WOLF-RAYET STAR WINDS |
| title_full | HIGH-RESOLUTION X-RAY SPECTROSCOPY REVEALS THE SPECIAL NATURE OF WOLF-RAYET STAR WINDS |
| title_fullStr | HIGH-RESOLUTION X-RAY SPECTROSCOPY REVEALS THE SPECIAL NATURE OF WOLF-RAYET STAR WINDS |
| title_full_unstemmed | HIGH-RESOLUTION X-RAY SPECTROSCOPY REVEALS THE SPECIAL NATURE OF WOLF-RAYET STAR WINDS |
| title_short | HIGH-RESOLUTION X-RAY SPECTROSCOPY REVEALS THE SPECIAL NATURE OF WOLF-RAYET STAR WINDS |
| title_sort | high resolution x ray spectroscopy reveals the special nature of wolf rayet star winds |
| url | http://hdl.handle.net/1721.1/95464 |
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