论文标题
在球状簇多个种群中产生的CA（和SC）过量：77个银河球状簇中的第一次人口普查
Excess of Ca (and Sc) produced in globular cluster multiple populations: a first census in 77 Galactic globular clusters
论文作者
论文摘要
球状簇（GC）中的多个恒星种群通过其光元素的不同丰度与众不同。丰度的抗相关表明由于高温H燃烧而导致核合成起源，但仍有待评估哪种恒星改变了GC中的原始丰度。特别是，在少数值得注意的情况（例如NGC 2419和NGC 2808）中检测到的钾和钙和扫描量的变化的非常高的温度下，仍在探索很差。相对于未修饰的田间恒星的水平，我们开始系统地搜索GC恒星中过量的CA（和SC）。在少数GC（NGC 4833，NGC 6715，NGC 6402，NGC 5296，NGC 5824和NGC 5139/Omega Centauri）中发现了这种过量的统计证据。我们首次表明NGC 4833可能会容纳反相关的K和MG丰度。所有这些GC是银河系中最大的GC之一。我们发现，在田间恒星分布上方3sigma处具有Ca增强的恒星的比例是GC质量和金属性的多元功能，就像GC中多重种群现象的其他表现一样。我们认为，仅在几个GC中进行的这些变化才能通过两个不同的通道来再现：要么所有GC共有的一类普通恒星，仅在特定环境中起作用，要么是由特殊类型的恒星（或缺乏这样的恒星）产生的。低金属性制度中渐近巨型分支星星的热底燃烧是一流的良好候选者。另外，超级质量恒星也预计也有金属性依赖性，预计将在大型GC中优先形成。 （简略）。
Multiple stellar populations in globular clusters (GCs) are distinct by their different abundances of light elements. The abundance anti-correlations point towards a nucleosynthesis origin due to high-temperature H burning, but it remains to be assessed which type of stars altered primordial abundances in GCs. In particular, the regime at very high temperature that shapes the variations in potassium as well as calcium and scandium, which has been detected in a few notable cases such as NGC 2419 and NGC 2808, is still poorly explored. We started a systematic search for excess of Ca (and Sc) in GC stars with respect to the level of unmodified field stars. Statistically robust evidence of such excess was found in a small number of GCs (NGC 4833, NGC 6715, NGC 6402, NGC 5296, NGC 5824, and NGC 5139/omega Centauri) that join the previously known two clusters. For the first time we show that NGC 4833 is likely to host anti-correlated K and Mg abundances. All these GCs are among the most massive ones in the Galaxy. We found that the fraction of stars with Ca enhancement at 3sigma above the field star distribution is a multivariate function of the GC mass and metallicity, as in other manifestations of the multiple population phenomenon in GCs. We argue that these alterations in only a few GCs can be reproduced by two different channels: either a class of ordinary stars, that is common to all GCs, acts only in particular environments, or an on-off mechanism is generated by the occurrence of a peculiar type of stars (or lack of such stars). Hot bottom burning in asymptotic giant branch stars in the low-metallicity regime is a good candidate for the first class. Alternatively, a metallicity dependence is also expected for supermassive stars, which are predicted to preferentially form in massive GCs. (abridged).
