| Project/Area Number |
20J23342
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| Research Category |
Grant-in-Aid for JSPS Fellows
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| Allocation Type | Single-year Grants |
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| Section | 国内 |
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| Review Section |
Basic Section 16010:Astronomy-related
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| Research Institution | Kyoto University |
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Principal Investigator |
方 其亮 (2020-2021) 京都大学, 理学研究科, 特別研究員(DC1)
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| Research Fellow |
方 其亮 (2022) 京都大学, 理学研究科, 特別研究員(DC1)
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| Project Period (FY) |
2020-04-24 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2022: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2021: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2020: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Supernvoa / Transient source / Spectroscopy / Spectrum |
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| Outline of Research at the Start |
This research will use a method that measures the mass of a star, developed by our previous work, and powerful telescopes, to investigate the physics process when the star explodes at the end of its life. With this method, we can also investigate how a star loss its weight before the explosion.
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| Outline of Annual Research Achievements |
We present the statistical analysis on the [Ca II] emission emerged in the nebular spectroscopy of core-collapse supernovae to study the configuration of the material expelled by the explosion.
In the previous researches, the analysis mainly focus on the [O I] line, which is emitted from the O-rich material that is not burnt by the explosive nucleosynthesis. The [Ca II] emitted from the explosive burning ash is seldom studied because the line profile is notoriously complicated.
In this work, we systematically investigate the relation between the profiles of [O I] and [Ca II]. We find double-peaked [O I] and [Ca II] are common. Moreover, the profiles of [O I] and [Ca II] are anti-correlated, i.e., these two emissions will not appear to be both double-peaked for the same object, which is a smoking gun of bipolar explosion (i.e., the explosion energy is released along a specific axis rather than released spherically).
By combining the profile [Ca II] and the progenitor mass of the supernova, we find clue that the occurrence rate of [Ca II] appears to be increasing with the carbon-oxygen core mass, which implies the supernova explosion becomes more axis-symmetric (or more non-spherical) as the progenitor mass increases. i.e., more massive stars lead to more aspherical explosions. Our results provide the first observational evidence on the mass-geometry relation of supernova, which is an important key to reveal the mechanism of the core-collapse.
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| Research Progress Status |
令和4年度が最終年度であるため、記入しない。
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| Strategy for Future Research Activity |
令和4年度が最終年度であるため、記入しない。
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