银河系铝元素丰度研究

Study on the Aluminum Abundance of Stars in the Milky Way

恒星的Al元素丰度可以为探索星团和星系的化学演化提供重要线索.通过系统分析银河系薄盘、厚盘、核球、银晕以及M4、M5等球状星团中恒星的[Al/Fe]随恒星金属丰度[Fe/H]的变化趋势,得出银河系薄盘、厚盘和核球恒星的[Al/Fe]随着[Fe/H]的增加而缓慢下降,而球状星团M4和M5恒星的[Al/Fe]随[Fe/H]增加没有下降趋势,这暗示Ia超新星对M4和M5恒星元素丰度的贡献比较小.详细研究了银河系恒星[Al/Fe]与[Mg/Fe]、[Na/Fe]的相关性,结果表明银河系场星的[Al/Fe]与[Mg/Fe]正相关,但在球状星团M4和M5恒星中未见此相关性;银河系盘星及M4和M5等球状星团恒星的[Al/Fe]与[Na/Fe]都存在正相关.

Al abundances of the stars can provide important clues for exploring the chemical evolution of the globular clusters and the galaxies.In this paper,we mainly study the trends of[Al/Fe]with the stellar metallicity in stars of the thin disk,thick disk,bulge,halo of the Galaxy,and the Galactic globular clusters,such as M4 and M5.Furthermore,we investigate the correlations of[Al/Fe]with[Mg/Fe]and[Na/Fe].For the stars in the thin disk,thick disk,and bulge of the Galaxy,their[Al/Fe]slowly decrease with the increasing[Fe/H].However,this decreased trend does not appear in stars of M4 and M5,which implies that the contributions from Type Ia supernovae to the elemental abundances of the stars in M4 and M5 are less than those to the field stars.There are positive correlations between[Al/Fe]and[Mg/Fe]of the field stars.However,this positive correlation between[Al/Fe]and[Mg/Fe]disappears in M4 and M5 stars.Variations of[Al/Fe]have correlations with[Na/Fe]in the Galactic disk stars and stars of globular clusters,such as M4 and M5.