...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Astronomy and astrophysics >Na-O anticorrelation and HB - VII. The chemical composition of first and second-generation stars in 15?globular clusters from GIRAFFE spectra
【24h】

Na-O anticorrelation and HB - VII. The chemical composition of first and second-generation stars in 15?globular clusters from GIRAFFE spectra

机译：Na-O抗相关性和HB-VII。 GIRAFFE光谱中15个球状星团中第一和第二代恒星的化学成分

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We present abundances of Fe, Na, and O for 1409 red giant stars in 15galactic globular clusters (GCs), derived from the homogeneous analysis ofhigh-resolution FLAMES/GIRAFFE spectra. Combining the present data with results from our FLAMES/UVES spectra and from previous studies within the project, we obtained a total sample of 1958 stars in 19clusters,the largest and most homogeneous database of this kind to date. The programme clusters cover a range in metallicity from [Fe/H] =-2.4dex to [Fe/H] =-0.4dex, with a wide variety of global parameters (morphology of the horizontal branch, mass, concentration, etc.). For all clusters we find the Na-O anticorrelation, the classical signature of the operation of proton-capture reactions in H-burning at high temperature in a previous generation of more massive stars that are now extinct. Using quantitative criteria (from the morphology and extension of the Na-O anticorrelation), we can define three different components of the stellar population in GCs. We separate a primordialcomponent(P) of first-generation stars, and two components of second-generation stars, that we name intermediate(I) and extreme(E) populations from their different chemical composition. The P component is present in all clusters, and its fraction is almost constant at about one third. The Icomponent represents the bulk of the cluster population. On the other hand, Ecomponent is not present in all clusters, and it is more conspicuous in some (but not in all) of the most massive clusters. We discuss the fractions and spatial distributions of these components in our sample and in two additional clusters (M3=NGC5272 and M13=NGC6205) with large sets of stars analysed in the literature. We also find that the slope of the anti-correlation (defined by the minimumO and maximum Naabundances) changes from cluster-to-cluster, a change that is represented well by a bilinear relation on cluster metallicity and luminosity. This second dependence suggests a correlation between average mass of polluters and cluster mass. Key words: stars: abundances - stars: atmospheres -stars: populationII - globular clusters: general
机译：我们提出了15个银河球状星团（GC）中1409个红色巨星的Fe，Na和O的丰度，这些均来自高分辨率FLAMES / GIRAFFE光谱的均质分析。将目前的数据与我们的FLAMES / UVES光谱结果以及该项目中的先前研究结果相结合，我们获得了19个团簇中1958颗恒星的总样本，这是迄今为止最大，最同类的数据库。该程序集群涵盖了从[Fe / H] = -2.4dex到[Fe / H] = -0.4dex的金属性范围，具有广泛的全局参数（水平分支的形态，质量，浓度等） 。对于所有星团，我们都发现了Na-O反相关性，这是上一代现已消失的更大型恒星在高温H燃烧中质子捕获反应操作的经典特征。使用定量标准（从Na-O反相关的形态和扩展），我们可以定义GC中恒星种群的三个不同组成部分。我们将第一代恒星的原始成分（P）和第二代恒星的两个成分分开，我们根据它们的不同化学成分来命名中间（I）和极端（E）总体。 P组分存在于所有簇中，其分数几乎恒定在大约三分之一。 Icomponent代表集群总体的大部分。另一方面，Ecomponent并非在所有集群中都存在，并且在某些（但不是全部）最庞大的集群中更为明显。我们讨论了样本中以及两个附加星团（M3 = NGC5272和M13 = NGC6205）中这些成分的比例和空间分布，其中有大量恒星在文献中进行了分析。我们还发现，反相关的斜率（由minimumO和最大Naabundances定义）在簇之间变化，这种变化可以很好地表示为簇金属度和发光度之间的双线性关系。第二种依赖性表明污染者的平均质量与集群质量之间的相关性。关键词：恒星：丰度-恒星：大气-恒星：人口II-球状星团：一般

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号