惰性气体氖和氩：在球状星团中多群体化学模式的作用？
Noble gases Neon and argon: a role for the chemical patterns of multiple populations in globular clusters?
AI总结：
研究通过调整氖和氩的丰度，探讨球状星团NGC 2808中极端群体的形成机制及多群体化学模式的作用。
摘要：
我们关注在达到高热底燃烧温度以在AGB模型中高效循环氧到氮所需的高温下，模型中钠的破坏情况。我们通过将初始氖丰度提高2-4倍，相对于通过将太阳值缩放至该星团金属度所获得的“标准”丰度，探索通过采用较小的质亏损率获得的抛射物平均丰度。更高的氖产生更多的钠在AGB包层中。降低质亏损率使能够保持相对较大的钠丰度并增加氧和镁的消耗。较低的质亏损率与不增加过多第三回卷事件的必要性之间的平衡，给出了氖丰度增加一倍，质亏损率减少四倍的最佳折中方案。与NGC 2808中的丰度相比，所有丰度模式都比标准模型有更好的一致性，但极端恒星（组E）需要略富铁的模型。因此，我们提出NGC 2808中的极端群体由金属度略小的恒星组成，并在恒星团分层组装框架内提出了其形成的可能性。组E中的钾丰度比标准模型高约0.2dex，但用初始氩的燃烧来解释则需要相关截面的大幅增加。在低金属度下氖和氩的丰度可能成为在球状星团AGB模型框架内更好地重现轻元素丰度的重要工具。
英文摘要：
We focus on the sodium destruction in models reaching the high hot bottom burning temperatures needed to efficiently cycle oxygen to nitrogen in AGB models at the nominal [Fe/H] of the cluster NGC 2808. We increase the initial neon abundance by a factor 2-4 with respect to the "standard" abundances obtained by scaling the solar values down to the metallicity of this cluster, and explore the average abundances in the ejecta obtained by adopting smaller mass-loss rates. Higher neon produces higher sodium in the AGB envelope. Lowering the mass-loss rate allows both to keep reasonably large sodium abundances and to increase the depletion of oxygen and magnesium. A balance between the lower mass-loss rates and the necessity of not increasing too much the episodes of third dredge up gives a neon abundance larger by a factor two and a mass-loss rate smaller by a factor four as best compromise. Comparison with the abundances in NGC 2808 shows a better agreement than the standard models for all the patterns of abundances, but the extreme stars (group E) requires models slightly less rich in iron. t Thus, we propose that the extreme population in NGC 2808 is composed of stars having a slightly smaller metallicity, and sketch a possible scenario for its formation, in the framework of the hierarchical clusters assembly scenario. Abundances of potassium are larger by $\sim 0.2 dex$ in the E group, but the explanation in terms of burning of the initial argon requires a drastic increase of the relevant cross section. The abundances of neon and argon at low metallicities may be an important tool to better reproduce the abundances of light elements in the framework of the AGB model for globular clusters.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
