Link between protoplanetary materials and interstellar dust

原行星材料与星际尘埃之间的联系

• 批准号: 13440059
• 负责人: YAMAMOTO Tetsuo
• 金额: $ 7.17万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13440059/
• 关键词: 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

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

研究了在agb后恒星中观测到的21微米波段的载流子。我们分析了von Helden等人（2000,Science, 288, 313）测量的TiC簇的红外光谱，并确定了21微米波段的吸收效率Q。利用Q值，我们估计了在21微米和11微米发射的agb后恒星红外光谱中观测到的21微米和11微米发射的通量比所需的Ti/Si丰度比。考虑到TiC颗粒被石墨快速包裹的凝结特性，我们计算了石墨包覆的TiC颗粒和其他可能的核幔颗粒的发射光谱，并与观测光谱进行了比较。丰度和缩合的考虑都强烈表明，在富含碳的agb后恒星周围，TiC是观测到的21微米红外特征的不太可能的载体。相关研究还包括：(1)分子团的实验室光谱研究；(2)尘埃在行星形成过程中的作用综述

项目成果

Y.Kimura: "Diffusion constant of hydrogen atoms in H2O+CO ice"Proc. 36th ISAS Lunar and Planetary Symp.. 36. 254-257 (2003)

Y.Kimura：“H2O CO 冰中氢原子的扩散常数”Proc。

千貝 健: "Are TiC grains a carrier of the 21 mirometer emission band observed around post-asymptotic giant branch post-AGB objects?"Astrophysical Journal. 587(in press). (2003)

Ken Chigai：“TiC 颗粒是在渐近巨分支后 AGB 天体周围观察到的 21 微米发射带的载体吗？”《天体物理学杂志》587（出版中）。

T.Chigai: "Condensation sequence of SiC and graphite grains around carbon stars"Geochimica et Cosmochimica Acta. Special Supplement. A63 (2003)

T.Chigai：“碳星周围碳化硅和石墨颗粒的凝结序列”Geochimica et Cosmochimica Acta。

山本 哲生: "ダストの物質進化からみた惑星形成"天文月報. 96・4(in Press). (2003)

Tetsuo Yamamoto：“从尘埃的物质演化中看到的行星形成”天文月报96・4（出版中）。

S.Hirabayashi: "Step-Scan Fourier-Transform infrared absorption spectroscopy of cubic solid acetylene clusters"Journal of Physical Chemistry A. Vol.107. 4829-4833 (2003)

S.Hirabayashi：“立方固体乙炔簇的步进扫描傅立叶变换红外吸收光谱”Journal of Physical Chemistry A. Vol.107。