Infrared absorption band at 7 mum of protostar dusts- An explanation with magnesium

原恒星尘埃 7 微米处的红外吸收带——镁的解释

基本信息

批准号：
07804014
负责人：
WADA Setsuko
金额：
$ 1.22万
依托单位：
The University of Electro-Gommunications
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07804014/
关键词：
Interstellar Dust Circumstellar Dust Infrared Absorption Spectrum Car bonate Dark Cloud Protostar 赤外線スペクトル塵

项目摘要

An infrared absorption band at a wavelength of 7 mum was observed in embedded protostars. Differences of the band width are seen in these objects. Up to now, various materials are proposed to the origin of the band, i.e., hydrocarbons, methanol, photolyzed mixtures of CO_2, H_2, NH_3 etc, and carbonates. We examined again infrared absorption bands of carbonate materials, pure carbonate, and mixtures of carbonate with oxides and hydroxides.Pure MgCO_3 and FeCO_3 show a peak at 6.83-6.85mum and 6.93-6.94mum, respectively. The features are very similar tothe 7 mum band shape observed in W33A,however these carbonates show additional subpeaks around 11mum region, which have not observed in protostars.We synthesized carbonate-oxide-hydroxide mixtures by (1) grinding oxides in CO_2 atmosphere, and (2) heating of magnesium carbonate hydroxide under vacuum. The products show a very broad band around 7 mum which is matched to the band observed in Mon R2 #2. In addition, the peak height of the subpeaks around 11mum of these materialsare very small.The main result is summarized as follows. Carbonates are good candidates for the 7 mum band of protostars though their spectra have some additional bands.

在嵌入的质子体中观察到了7妈妈的波长的红外吸收带。在这些对象中可以看到频带宽度的差异。到目前为止，提出了各种材料，即带有碳氢化合物，甲醇，Co_2，H_2，NH_3等的光解混合物和碳酸盐的碳酸，甲醇，光解混合物。我们再次检查了碳酸盐材料，纯碳酸盐和碳酸盐与氧化物和氢氧化物的混合物的红外吸收带。PUREMGCO_3和FECO_3分别显示出峰值为6.83-6.85mum和6.93-6.94.94mum。这些特征非常相似，在W33a中观察到了7个妈妈的带状形状，但是这些碳酸盐在11MUM区域中显示出额外的子峰，在Protostar中尚未观察到，我们合成了碳酸盐 - 氧化物 - 氧化物 - 羟基混合物（1）在CO_2大气中通过（1）在CO_2大气中研磨氧化物，以及（2）降温碳酸盐含量下的碳酸盐氧化碳酸盐氧化物。该产品显示出一个非常宽的带子，大约7个妈妈，与Mon R2＃2中观察到的频段相匹配。此外，凸面的峰值高度在这些材料中的11mum左右很小。主要结果总结如下。碳酸盐是7妈妈的原始恒星带的好候选者，尽管它们的光谱还有一些额外的频带。