AGB星的ISO观测

AGB stars seen by ISO

概述了ＩＲＡＳ升空以来在ＡＧＢ星研究方面的进展和发现的问题，比较详细地报告了６０ｃｍ空间红外望远镜ＩＳＯ携带的探测器及其性能，以及它的成像和光谱观测对研究ＡＧＢ星的演化的影响，尤其是对ＡＧＢ星星周包层的化学环境的研究的重要作用．

This paper reports the progress in ISO (Infrared Space Observatory) project and putsemphasis on its influence on the study of AGB stairs. Because AGB stars lose mass in large scaleand become mostly optically thick, infrared observations can be used to exhibit the gas/dustcomponents of the circumstellar envelopes. Furthermore, the circumstellar envelope of AGB starsis a very important source for the evolution of interstellax medium, and a clear understanding ofthe AGB stars' circumstellar envelope will help investigate the evolution of cosmic abundances.ISO spoilt quite a lot of time on observations of AGB stars with various methods includingimaging, spectroscopy, polarimetry and photometry with higher resolution, better sensitivity andwider wavelength coverage than those of the first infrared astronomical satellite IRAS. Thoughthis space infrared obserwtory finished its mission just in May 1998, already some useful resultshave been published. Detached shell structure of AGB stars seen from ISO photo-imaging impliesnon-colltinuous mass loss process. Compared with previous observations obtained from IRAS andground telescopes, ISO reveals more complete spectrum of some molecules such as HCN, CO andPAH. In addition, ISO discoveres maily new lines, some of which have been identified, while manyof which are yet to be identified. In particulax, the dust features are abundant in the spectra ofAGB stars. In the upcoming years, more laboratory work is needed and a good understanding ofthe mass loss and circumstellar components of AGB stars can be expected.