Nitrogen enrichment and clustered star formation at the dawn of the Galaxy
Nitrogen enrichment and clustered star formation at the dawn of the Galaxy
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银河系黎明时的氮富集和星团形成
DOI：
10.1093/mnras/stad2241
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发表时间：
2023
影响因子：
4.8
通讯作者：
Kravtsov, Andrey
中科院分区：
文献类型：
--
作者：
Belokurov, Vasily;Kravtsov, Andrey
在球状星团（GC）、银河系的场星（MW）中，甚至在AZ 11星系的气体中，都观测到了异常高的氮氧丰度比[N/O]。使用的数据从APOGEE数据Release 17和theGaia数据Release 3，我们提出了几个独立的证据，大多数MW的高[N/O]恒星出生在大规模的绑定集群在早期，前盘星系的演变。具体来说，我们表明，分布的金属丰度[Fe/H]，能量，角动量Lz，和低金属丰度高[N/O]星的距离匹配的极光人口和在situGC的恒星的相应分布。我们还发现，fN/O随金属丰度的降低而迅速增加。在金属丰度从到演变的时期，银河系旋转起来，从湍流的极光状态过渡到相干旋转的圆盘。这种转变伴随着许多质的变化。特别是，我们发现，高N/O丰度类似于在GN-z11中观察到的那些是常见的自旋前（），当高达的原位恒星形成在大质量的束缚星系团。N/Oat的急剧下降表明，在圆盘出现后，形成大质量束缚星团的恒星比例减少了两个数量级。
Anomalously high nitrogen-to-oxygen abundance ratios [N/O] are observed in globular clusters (GCs), among the field stars of the Milky Way (MW), and even in the gas in az≈ 11 galaxy. Using data from the APOGEE Data Release 17 and theGaiaData Release 3, we present several independent lines of evidence that most of the MW’s high-[N/O] stars were bornin situin massive bound clusters during the early, pre-disc evolution of the Galaxy. Specifically, we show that distributions of metallicity [Fe/H], energy, the angular momentumLz, and distance of the low-metallicity high-[N/O] stars match the corresponding distributions of stars of theAurorapopulationandof thein situGCs. We also show that the fraction ofin situfield high-[N/O] stars,fN/O, increases rapidly with decreasing metallicity. During epochs when metallicity evolves fromto, the Galaxy spins up and transitions from a turbulent Aurora state to a coherently rotating disc. This transformation is accompanied by many qualitative changes. In particular, we show that high N/O abundances similar to those observed in GN-z11 were common before the spin-up () when up toof thein situstars formed in massive bound clusters. The dramatic drop offN/Oatindicates that after the disc emerges the fraction of stars forming in massive bound clusters decreases by two orders of magnitude.