2020 Fiscal Year Final Research Report
Are merger remnants of binary white dwarfs observable by spaceborne gravitational-wave detectors?
| Project/Area Number |
18K03641
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | 白色矮星 / 連星 / 重力波 |
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| Outline of Final Research Achievements |
A close binary composed of two white dwarfs emits gravitational wave and finally merges to form a single remnant. In this research
I studied characteristic oscillations of rapidly rotating remnants. The oscillations modes of interest here are in the frequency range of 0.1 Hz (decihertz). The frequency range is in the observable window of such planned space-borne gravitational wave observatories as DECIGO (DECI-hertz Gravitational Observatory) and BBO (Big Bang Observer). Here I numerically constructed the remnant models of the mergers and computed the unstable eigenmode oscillations of them. I also computed the amplitude of gravitational waves from the oscillations. By this study it is shown that the remnant's oscillations are observable with the planned space-borne gravitational wave observatory.
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| Free Research Field |
理論宇宙物理学
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| Academic Significance and Societal Importance of the Research Achievements |
近接する白色矮星連星の合体は，熱核融合型（Ia型）超新星爆発の前駆天体として，また質量の大きな，あるいは磁場の強い白色矮星を作る過程として興味深い現象である．今回の研究では，これまで議論されていなかった，合体直後に残された残存天体からの重力波放射について，全く新たな可能性を提案できた．周波数0.1Hz帯での重力波観測において，これは新たなターゲット天体となるだろう．また，Ia型超新星爆発が合体に引き続き起きるならば，一連の過程において重力波と電磁波によるマルチメッセンジャー観測も期待できることを示唆できた．
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