PRIMORDIAL r-PROCESS DISPERSION IN METAL-POOR GLOBULAR CLUSTERS
PRIMORDIAL r-PROCESS DISPERSION IN METAL-POOR GLOBULAR CLUSTERS
复制标题
贫金属球状团簇中的原始 r 过程弥散
DOI：
10.1088/2041-8205/732/1/l17
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
I. Roederer
中科院分区：
文献类型：
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作者：
I. Roederer
传统上，除了少数贫金属球状星团（GC）外，中子俘获反应产生的重元素在所有星团中都没有星与星星之间的分散。最近检测到的低[Pb/Eu]的比率或上限在几个贫金属GC表明，在这些GC中的重元素完全由r-过程产生。重新检查GC重元素丰度从文献中，我们发现明确无误的相关性之间的[La/Fe]和[Eu/Fe]比值在四个贫金属GC（M5，M15，M92，和NGC 3201），其中只有两个是已知的。这表明，总的r-过程的丰度变化从星星到星星（2-6倍）相对于每个GC内的铁。我们还确定了其他两个GC（M3和M13）的潜在分散。几个GC（M12，M80和NGC 6752）没有显示r过程分散的证据。r-过程色散与众所周知的轻元素色散无关，这表明它存在于整个星星形成期间的气体中。目前的观测结果表明，恒星到星星r-过程中的分散在金属贫乏的GC可能是一个常见的，但不是普遍存在的现象，既不是预测，也不占在目前的GC形成和演化模型。
Heavy elements, those produced by neutron-capture reactions, have traditionally shown no star-to-star dispersion in all but a handful of metal-poor globular clusters (GCs). Recent detections of low [Pb/Eu] ratios or upper limits in several metal-poor GCs indicate that the heavy elements in these GCs were produced exclusively by an r-process. Re-examining GC heavy element abundances from the literature, we find unmistakable correlations between the [La/Fe] and [Eu/Fe] ratios in four metal-poor GCs (M5, M15, M92, and NGC 3201), only two of which were known previously. This indicates that the total r-process abundances vary from star to star (by factors of 2–6) relative to Fe within each GC. We also identify potential dispersion in two other GCs (M3 and M13). Several GCs (M12, M80, and NGC 6752) show no evidence of r-process dispersion. The r-process dispersion is not correlated with the well-known light element dispersion, indicating that it was present in the gas throughout the duration of star formation. The observations available at present suggest that star-to-star r-process dispersion within metal-poor GCs may be a common but not ubiquitous phenomenon that is neither predicted by nor accounted for in current models of GC formation and evolution.