Blue Straggler Stars in Galactic Open Clusters and the Simple Stellar Population Model
Blue Straggler Stars in Galactic Open Clusters and the Simple Stellar Population Model
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DOI：
10.1086/512964
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发表时间：
2006-09
期刊：
影响因子：
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通讯作者：
Xin Yuxin;Licai Deng;Zhanwen Han
中科院分区：
文献类型：
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作者：
Xin Yuxin;Licai Deng;Zhanwen Han
蓝离散星作为银河系疏散星团的安全成员，对传统的简单星族模型提出了重大挑战。这些都是基于单星的恒星演化理论，而BS的主要形成机制都与恒星相互作用有关。我们在以前的一项研究中已经说明了这一点，该研究基于一个小样本的旧（年龄≥1 Gyr）银河系OC。然而，为了在统计上和系统地展示BS对传统SSP模型的贡献，绝对需要具有足够年龄和金属丰度覆盖的大型数据库。工作样本现在包括100个银河OC，年龄从0.1到10 Gyr不等。在单个簇的基础上计算BS对其宿主簇的集成光的贡献。在我们的星星集群样本中BS的普遍存在极大地改变了传统SSP模型在其综合性质方面的预测。忽略恒星群体中非标准演化产物（如BS）的后果，在无法分辨的条件下，在分析其积分光谱能量分布时会产生非常大的不确定性。目前的工作强烈建议，当使用演化布居合成技术来研究星系中未分辨恒星布居的性质时，应该考虑BS的贡献。
The presence of blue straggler stars (BSs) as secure members of Galactic open clusters (OCs) poses a major challenge to the conventional picture of simple stellar population (SSP) models. These are based on the stellar evolution theory of single stars, whereas the major formation mechanisms of BSs are all correlated with stellar interactions. We have illustrated this in a previous study based on a small sample of old (age ≥1 Gyr) Galactic OCs. However, for the purpose of demonstrating the contributions of BSs to the conventional SSP models statistically and systematically, a large database with sufficient coverage of age and metallicity is definitely needed. The working sample now includes 100 Galactic OCs with ages ranging from 0.1 to 10 Gyr. The contributions of BSs to the integrated light of their host clusters are calculated on an individual cluster basis. The general existence of BSs in our star cluster sample dramatically alters the predictions of conventional SSP models in terms of their integrated properties. Neglecting the consequences of nonstandard evolutionary products, such as BSs, in stellar populations, very large uncertainties can be made in analyzing their integrated spectral energy distributions at unresolvable conditions. The current work strongly suggests that when evolutionary population synthesis technique is used to study the properties of unresolved stellar populations in galaxies, the contributions of BSs should be taken into account.