1991 Fiscal Year Final Research Report Summary
Co-operative Study of Compact and Diffuse Remnants in Supernova 1987A
| Project/Area Number |
02302024
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理学一般
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| Research Institution | University of Tokyo |
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Principal Investigator |
NOMOTO Ken'ichi Univ.of Tokyo, Astronomy, Associate Professor, 理学部, 助教授 (90110676)
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| Co-Investigator(Kenkyū-buntansha) |
TSUNEMI Hiroshi Osaka University, Physics, Associate Professor, 理学部, 助教授 (90116062)
TAKATSUKA Tatsuyuki IWATE University, Physics, Professor, 人文社会科学部, 教授 (50043427)
MATSUDA Takuya Kyoto University, Aerodynamics, Assoriate Professor, 工学部, 助教授 (20026206)
KOYAMA Katsuji Kyoto University, Physics, Professor, 理学部, 教授 (10092206)
KAMAE Tsuneyoshi Univ.of Tokyo, Physics, Professor, 理学部, 教授 (90011618)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Supernova / Neutrino / X-ray / gamma-ray / Cosmic Ray / Dust / Pulsar / Neutron Star |
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| Research Abstract |
SN 1987A provides us with an excellent material to test the theory of massive star evolution, nucleosynthesis, and supernova explosion. Presupernova evolution of the progenitor, hydrodynamics of explosion, explosive nucleosynthesis, optical, X-ray and gamma-ray light curves due to ^<56>Co decay are calculated and compared with the observations of SN 1987A.
1. The unique evolution of the progenitor in the HR diagram can be understood in terms of mass loss and mixing. The mass loss drives the star to move from a blue to red supergiant. The excursion from the red back to the blue occurs if the hydrogen-rich envelope is metal deficient and becomes sufficiently helium-rich due to mixing.
2. The light curves in all wave bands indicate the explosion energy of E/M<@D2env@>D2=1.5(]SY.+-。[)0.5*10<@D150@>D1 erg/M<@D2(]SY.sun.[)@>D2, production of <@D156@>D1Ni with M<@D2Ni@>D2-0.07M<@D2(]SY.sun.[)@>D2. The plateau-like peak is found to be formed by the hydrogen recombination front and lasts longer if the hydrogen layr is deeper. This indicates the mixing of hydrogen into the deep interior.
3. The distribution of heavy elements in the ejecta is inferred also from the X-ray and gamma-ray light curves. The early emergence of X-ray and gamma-ray indicate the mixing of ^<56>Ni into the hydrogen-rich envelope. Flat X-ray light curve observed by Ginga would be due to the clumpy structure of the core.
4. Such a mixing is well modeled by the Rayleigh-Taylor instabilities during explosion. Two-dimensional hydrodynamical simulations have shown that the instability grows at the hydrogen/helium interface and mixes the supernova meterials.
5. The recent slowdown of the decline of the optical light curve is due to the contribution from another energy source, which would be either radioactive ^<56>Co or the buried neutron star. Recent balloon experiments have provided the upper limit to ^<57>Co and suggested that the pulsar activity is more likely the source.
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