The Populations of Carina. II. Chemical Enrichment
The Populations of Carina. II. Chemical Enrichment
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卡里纳的人口。
DOI：
10.3847/1538-4365/aa755e
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
A. Dotter
中科院分区：
文献类型：
--
作者：
J. Norris;D. Yong;K. Venn;G. Gilmore;L. Casagrande;A. Dotter
基于我们自己的观测结果（32 颗恒星）的均匀 1D/LTE 模型大气分析和文献中的可用数据（另外 31 颗独立恒星），显示了船底座矮球星系 (dSph) 中 63 颗红巨星样本中 19 种元素的化学丰度。 (Fe)金属丰度和[α/Fe]分布函数的平均值和离散度分别为-1.59和0.33 dex（[Fe/H]范围：-2.68至-0.64）和0.07和0.13 dex（[α/Fe]范围：-0.27至0.25）。我们证实了维恩等人的发现。一小部分样本（在本次调查中约为 10%）显示出 Ia 型超新星 (SN Ia) 喷射物显着富集的明确证据。钙，具有最准确确定的 α 元素丰度，在所有 [Fe/H] 下显示出朝向较小 [Ca/Fe] 值的不对称分布，最明显的是超过 -2.0 < [Fe/H] < -1.0，这表明超新星 Ia 的喷射物与船底座每一代的环境介质不完全混合。给出了样本的近似颜色-幅度图年龄估计，并与我们的化学丰度一起，与我们之前的合成颜色-幅度图分析的结果进行了比较，该分析报告了卡里纳四个明确定义的种群的详细信息。我们搜索了银河系球状星团中普遍报道的Na-O反相关性，并证实这种现象在船底座不存在。我们还发现，样本中的 32 颗恒星中的一颗的锂丰度极高——A(Li)NLTE = +3.36，这与 Kirby 等人描述的 dSph 中约 1% 的富锂恒星组的成员资格一致。
Chemical abundances are presented for 19 elements in a sample of 63 red giants in the Carina dwarf spheroidal galaxy (dSph), based on homogeneous 1D/LTE model atmosphere analyses of our own observations (32 stars) and data available in the literature (a further 31 independent stars). The (Fe) metallicity and [α/Fe] distribution functions have mean values and dispersions of −1.59 and 0.33 dex ([Fe/H] range: −2.68 to −0.64) and 0.07 and 0.13 dex ([α/Fe] range: −0.27 to 0.25), respectively. We confirm the finding of Venn et al. that a small percentage (some 10% in the present investigation) of the sample shows clear evidence for significant enrichment by Type Ia supernova (SN Ia) ejecta. Calcium, with the most accurately determined abundance of the α-elements, shows an asymmetric distribution toward smaller values of [Ca/Fe] at all [Fe/H], most significantly over −2.0 < [Fe/H] < −1.0, suggestive of incomplete mixing of the ejecta of SNe Ia with the ambient medium of each of Carina’s generations. Approximate color–magnitude diagram age estimates are presented for the sample, and together with our chemical abundances, compared with the results of our previous synthetic color–magnitude diagram analysis, which reported the details of Carina’s four well-defined populations. We searched for the Na–O anticorrelation universally reported in the Galaxy’s globular clusters and confirm that this phenomenon does not exist in Carina. We also found that one of the 32 stars in our sample has an extremely enhanced lithium abundance—A(Li)NLTE = +3.36, consistent with membership of the ∼1% group of Li-rich stars in dSph described by Kirby et al.
DOI：
10.1111/j.1365-2966.2012.21859.x
发表时间：
2012-11-01
影响因子：
4.8
作者：
Korobkin, O.;Rosswog, S.;Winteler, C.
通讯作者：
Winteler, C.