环恒星环境中的碳化纳米晶体
G von Helden1, A G Tielens, D van Heijnsbergen
1FOM Institute for Plasma Physics Rijnhuizen, Edisonbaan 14, NL-3430 BE Nieuwegein, Netherlands. gertvh@rijnh.nl
Science (New York, N.Y.)
|April 15, 2000
概括
来自石的碳化纳米晶体已经在垂死的恒星中被光谱识别出来. 这一发现证实了这些前太阳颗粒在短暂而强烈的质量丧失阶段的恒星起源.
科学领域:
- 天体化学是天体化学.
- 恒星进化 恒星进化
- 宇宙尘埃的形成
背景情况:
- 石含有前极石墨和碳化颗粒.
- 同位素分析表明,非对称巨分支 (AGB) 恒星是它们的起源.
- 在天文来源中缺乏这些粒的直接观测证据.
研究的目的:
- 在天文来源中提供碳化物 (TiC) 颗粒的直接观测识别.
- 将实验室测量的TiC纳米晶体光谱与天体物理观测联系起来.
- 为了限制TiC形成的条件和恒星相.
主要方法:
- 气相碳化纳米晶体的实验室合成.
- 测量合成的TiC纳米晶体的红外 (IR) 光谱.
- 实验室光谱与进化恒星的天文红外光谱的比较.
主要成果:
- 实验室TiC纳米晶体在20.1微米处表现出一个突出的光谱特征.
- 类似的光谱特征也被观察到在后非对称巨分支 (后AGB) 恒星中.
- 光谱匹配提供了强有力的证据,证明了这些恒星环境中的TiC粒.
结论:
- 碳化是在垂死,低质量恒星的流出中形成的.
- 形成发生在灾难性质量损失的短,强烈阶段 (大约. 100年) 的时间.
- 这证实了AGB和AGB后的恒星是太阳前谷物生产的关键地点.
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