| Co-Investigator(Kenkyū-buntansha) |
TANAKA Wataru University of Tokyo, Faculty of Science, 理学部, 助手 (20011570)
NAKADA Yoshikazu University of Tokyo, Faculty of Science, 理学部, 助手 (80011740)
SAIO Hideyuki University of Tokyo, Faculty of Science, 理学部, 助手 (10162174)
ONAKA Takashi University of Tokyo, Faculty of Science, 理学部, 助手 (30143358)
SHIBAHASHI Hiromoto University of Tokyo, Faculty of Science, 理学部, 助手 (30126081)
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| Budget Amount *help |
¥35,700,000 (Direct Cost: ¥35,700,000)
Fiscal Year 1988: ¥14,000,000 (Direct Cost: ¥14,000,000)
Fiscal Year 1987: ¥21,700,000 (Direct Cost: ¥21,700,000)
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| Research Abstract |
In recent years, very accurate observations revealed the fact that the sun and various kind of stars, including magnetic variables, while dwarfs and early-type stars, are oscillating in their various eigenmodes. This opened new fields of research called "helioseismology" and "asteroseismology", in which we try to probe interiors of the sun and those stars, which had been inaccessible to any other observation, by analyzing their eigenoscillations. The objective of our project has been to construct methodology in helioseismology and asteroseismology both observationally and theoretically, and to study internal structures of the sun and stars by those seismological approach. A brief description of our results are given below.
1. We discussed effect of r-mode oscillations to line profiles in rapidly rotating early-type stars, as a possible explanation to line profile variation in spectra of those stars. 2. We developed an effective method of identifying eigenmodes which contribute to variat
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ions in line profiles, based on Fourier analysis in time and wavelength. 3. The method described above was applied to observational data of be stars, and we succeeded in identifying some eigenmodes. Particularly, we found that an identical set of mdoes contributes to line profily variation all through a quiescence phase of Oph. 4. We developed a method of solving an inverse problem of solar p-mode spectra, utilizing asymptotic analysis, to infer the sound velocity distribution in the solar interior was developed. Further, the property of othe method in practical numeric process was studied. 5. We applied the method described above to a published observational data, and compared the resultant distribution of sound velocity with that of a standard model. 6. We developed another inverse method which has general possible targets, though restricted to linear inverse problem. 7. We develope a method of solving an inverse problem of g-mode spectra of white dwarfs, utilizing asymptotic analysis, to infer the distribution of Brunt-Vaisala frequency in those stars. 8. Rapid oscillations in magnetic Ap stars are analyzed to renew mode identification. Less
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