X-ray emission by a shocked fast wind from the central stars of planetary nebulae |
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| Authors: | Muhammad Akashi Noam Soker Ehud Behar |
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| Institution: | Department of Physics, Technion –Israel Institute of Technology, Haifa 32000, Israel |
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| Abstract: | We calculate the X-ray emission from the shocked fast wind blown by the central stars of planetary nebulae (PNe) and compare with observations. Using spherically symmetric self-similar solutions, we calculate the flow structure and X-ray temperature for a fast wind slamming into a previously ejected slow wind. We find that the observed X-ray emission of six PNe can be accounted for by shocked wind segments that were expelled during the early-PN phase, if the fast wind speed is moderate, v 2～ 400–600 km s?1 , and the mass-loss rate is a few times 10?7 M⊙ yr?1 . We find, as proposed previously, that the morphology of the X-ray emission is in the form of a narrow ring inner to the optical bright part of the nebula. The bipolar X-ray morphology of several observed PNe, which indicates an important role of jets, rather than a spherical fast wind, cannot be explained by the flow studied here. |
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| Keywords: | stars: mass-loss stars: winds outflows X-rays: ISM |
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