1988 Fiscal Year Final Research Report Summary
Theoretical Models for Supernova with Peculiar Light Curves
| Project/Area Number |
62540183
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Astronomy
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| Research Institution | University of Tokyo |
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Principal Investigator |
NOMTO Ken'ichi University of Tokyo, 教養学部, 助教授 (90110676)
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| Co-Investigator(Kenkyū-buntansha) |
ERIGUCHI Yoshiharu University of Tokyo, 教養学部, RESEARCH (80175231)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Supernova / SN 1987A / X-ray / -ray / Radioactivity / nucleosynthesis / Pulsar |
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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 -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_<env> = 1.5 0.5 X 10^<50> erg/M<of sun>, production of ^<56>Ni with M_<Ni> - 0.07 M<of sun>. The plateau-like peak is found to be formed by the hydrogen recombination front and lasts longer if the hydrogen layer 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 -ray light curves. The early emergence of X-ray and -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.
If the recent slowdown of the decline of the optical light curve is due to the contribution from another energy source, it would be either radioactive ^<57>Co or the buried neutron star. We offer predictions for future light curves.
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