| Project/Area Number |
13440059
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | Nagoya University |
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Principal Investigator |
YAMAMOTO Tetsuo Nagoya Univ., Dept.Earth & Planet, Professor, 大学院・環境学研究科, 教授 (10126196)
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| Co-Investigator(Kenkyū-buntansha) |
KOZAWA Takeshi Hokkaido Univ., Dept.Earth & Planet, Professor, 大学院・理学圏研究科, 教授 (90263368)
WATANABE Sei'ichiro Nagoya Univ., Dept.Earth & Planet, Professor, 大学院・環境学研究科, 助教授 (50230967)
HIRAYAMA Yasuhiro Nagoya Univ., Dept.Earth & Planet, Professor, 大学院・環境学研究科, 助教授 (30252224)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥11,200,000 (Direct Cost: ¥11,200,000)
Fiscal Year 2003: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2002: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2001: ¥6,100,000 (Direct Cost: ¥6,100,000)
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| Keywords | Nucleation / cosmic dust / interstellar matter / meteorites / planets / protoplanetary materials / material evolution in space / ダスト / Presolar grains / TiC / グラファイト / 物質進化 / 粘弾性 / 赤外線分光 / 惑星原物質 / 星間ダスト / プレソーラー粒子 / ダスト生成 |
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| Research Abstract |
The carrier of the 21-micron-band observed in the post-AGB stars is examined. We analyze the infrared spectra of the TiC clusters measured by von Helden et al. (2000, Science, 288, 313) and determine the absorption efficiency Q in the 21-micron-band. Using the Q, we estimate the Ti/Si abundance ratios needed to realize the flux ratios of the 21-and 11-micron emissions observed in the infrared spectra of the post-AGB stars exhibiting both 21-and 11-micron emissions. In view of the nature of the TiC condensation that TiC grains are quickly mantled by graphite, we calculate the emission spectra of the graphite-coated TiC grains and other possible types of core-mantle grains, and compare with the observed spectra. Both of the abundance and condensation considerations strongly suggest that TiC is an implausible carrier of the observed infrared 21-micron feature around carbon-rich post-AGB stars.
The following relevant study has also been carried out :
(1) Laboratory spectrosocpic study of molecular clusters,
(2) Review of the role of dust in formation of the planets
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