研究进展：双星星族模型成功解释了球状星团的不同UV波段表现

双星拟合小组 李忠木

2013年6月3日

       此前的观测研究结果中金属丰度和年龄均类似的球状星团却表现出了截然不同的紫外光谱形态：其中一类的紫外能流随波长减小而上升（即紫外能流反转现象），而另一类的紫外能流则随波长减小而下降。对这样的表现大家一直非常迷惑，因为根据天文研究的最重要工具之一——演化星族合成理论，具有类似星族年龄和金属丰度的简单星族应该具有类似的光谱特征。

       最近由李忠木博士带领的双星拟合小组（BS2fit group）通过双星复合星族模型对这些光谱进行了详细研究，结果表明：用双星星族模型进行研究时，这些紫外表现不同的光谱实际上对应着不同的星族金属丰度和年龄，有紫外反转的光谱对应的金属丰度和年龄均更大。但是利用单星星族合成模型进行同样的研究得到的两类光谱的对应星族金属丰度和年龄却非常相似。因此，我们的结果表明双星星族合成模型能够更好地对观测结果进行解释，也是获得天体真实星族成分的必要工具。

Research Progress：Binary Star Stellar Population Model Gives New Insight into UV-Different Spectra of Globular Clusters

BS2fit group Dr. Zhongmu Li

Globular Clusters in the Galaxy, LMC, and SMC show different UV spectra, although they have similar stellar metallicities and ages (estimated by single star stellar population models). Astronomers feel strange for such results, because simple stellar populations (SSPs) should have similar spectra if their metallicities and ages are similar, according to one of most important tools for astrophysical studies, i.e., evolutionary population synthesis.

Recently, bianry star to fit group (BS2fit group) studied the various spectra of clusters in detail. The results show that when binary star stellar population (bsSP) models are used instead of single star stellar population (ssSP) models, the spectra with or without UV-upturn corresponds to different stellar metallicities and ages. Those with UV-upturn are actually from stellar populations with richer metallicities and older ages.

Our resutls therefore suggest that bsSP models are important for give correct explanations to spectra of globular clusters, and it may also be an special tool in astrophysical studies.