Observational study of the relation between the AGB evolution and the space distribution of AGB stars

在渐近巨支恒星空间分布的基础上，研究了渐近巨支恒星的演化。AGB有两种类型：碳星和m型星。我们怀疑这两类恒星的空间分布是不同的，AGB恒星在整个银河系的演化顺序也不一样。要弄清碳星和m型星在银河系中不同位置的演化序列的差异或相似性，有必要了解它们的空间分布。为了得到碳星的空间分布，我们进行了近红外光度观测，并估算了单个碳星的总辐射能量（TRE）。通过与假定本征光度的比较，计算了碳星的距离，得到了碳星的空间分布。通过分析IRAS观测的光度数据，得到了m型恒星的空间分布。对比碳星和m型星的空间分布，我们发现两者的分布是不同的。这一结果表明，AGB恒星的演化顺序在整个星系中并不相同。

We have investigated the evolution of asymptotic giant branch (AGB) stars on the basis of the space distribution of AGB stars. There are two kinds of AGB stars : Carbon stars and M-type stars. We suspect that the space distributions of these two-types of stars are different from each other and that the evolutionary sequence of AGB stars is not the same in the whole Galaxy. To clarify the difference or the similarity of the evolutionary sequence depending on the location in the Galaxy, it is essential to know the space distribution of carbon stars and M-type stars. To get the space distribution of carbon stars we carried out near-infrared photometric observations and estimated total radiant energies (TRE) from individual carbon stars. By comparing the TRE with assumed intrinsic luminosity, distances of carbon stars are evaluated and then we obtained the space distribution of carbon stars. The space distribution of M-type stars is obtained by analyzing the photometric data of IRAS observations. Comparing the space distributions of carbon stars and M-type stars, we have found that two distributions are different from each other. This result shows that the evolutionary sequence of AGB stars is not the same in the whole galaxy.