2006 Fiscal Year Final Research Report Summary
Studies on x-ray emission mechanisms of stars by a collisional-radiative model including effects of radiation transfer
| Project/Area Number |
16540221
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | Nagoya University |
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Principal Investigator |
YAMAMOTO Norimasa EcoTopia Science Institute, Researcher, エコトピア科学研究所, 研究員 (40350326)
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| Co-Investigator(Kenkyū-buntansha) |
KOHMURA TAKAYOSHI Kogakuin University, Assistant Professor, 工学部, 専任講師 (20365505)
KITAMOTO SHUNJI Rikkyo University, Professor, 理学部, 教授 (70177872)
SHIBAZAKI NORIAKI Rikkyo University, Professor, 理学部, 教授 (50206124)
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| Project Period (FY) |
2004 – 2006
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| Keywords | collisional-radiative model / early type stars / X-ray emission mechanism / X-ray spectra / iron |
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| Research Abstract |
Our research goal is to elucidate X-ray emission mechanisms of stars. To accomplish our study, at first we developed a new collisional-radiative model of stellar wind from stars including the radiation transfer. Next we applied our stellar wind model to the observed X-ray spectral lines with X-ray satellites to reveal the X-ray emitted region around stars, the density of the stellar wind, the temperature of the stellar wind, and so on.
The result of our study is as follows.
(1) Developments of a high precise collisional-radiative model of various helium-like (C, N, O, Ne, Mg, Si, S) ions. Inclusions of radiation transfer by Monte Carlo method are at a stage of a toy model.
(2) Developments of a collisional-radiative model on KLM-shell Fe ions and applications to laboratory plasma. The model for Fe ions was applied to helical plasmas (large helical device (LHD) at the National Institute for Fusion Science) for highly precise modeling.
(3) Constructions of a Doppler model including three components, the doppler shift derived from a velocity distribution of stellar winds, absorptions by mediums in stellar winds, and filling factors.
(4) Analysis of early type stars obtained with X-ray satellites (Chandra and XMM-Newton) by the doppler model, and discussions of X-ray emission regions around stars. Furthermore X-ray emission spectra of stars by Suzaku satellite (launched in 2005) were analyzed. We obtained that x-ray emission regions of zeta-pup are near a star, on the other hand these of tau-sco are far from a star (Yamamoto et al.2007).
We plan as follows, more precise analysis of x-ray emission spectra, a development from current toy model to a practical radiation transfer model, researches of practical non-equilibrium plasma model. Then, astronomical plasmas and solar plasmas are analyzed by the model.
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Research Products
(10 results)
