Galactic evolution of nitrogen
Galactic evolution of nitrogen
复制标题
氮的银河演化
DOI：
10.1051/0004-6361:20047132
复制
发表时间：
2004
影响因子：
6.5
通讯作者：
P. Molaro
中科院分区：
文献类型：
--
作者：
G.Israelian;A. Ecuvillon;R. Rebolo;R. G. López;P. Bonifacio;P. Molaro
我们提出了详细的光谱分析的氮丰度在31个未进化的贫金属恒星的光谱合成的近紫外NH波段在3360 A高分辨率观察到的各种望远镜分析。我们发现，在金属丰度范围为−3.1 <（Fe/H）< 0时，（N/Fe）与铁的比例成正比，斜率为0.01 ± 0.02。此外，我们得到均匀和准确的（N/O）比使用氧丰度从近紫外OH线在我们以前的研究中获得的。我们发现，氮的主要成分是需要解释的意见。在极贫金属亚矮星G64-12和LP 815 -43的VLT/UVES光谱中发现了NH线，表明这两颗星是富N的。并与河外H Ⅱ区和阻尼Lyα系统的理论模型和观测结果进行了比较。这是第一次直接比较这些物体与银河系恒星的（N/O）比。
We present detailed spectroscopic analysis of nitrogen abundances in 31 unevolved metal-poor stars analysed by spectral synthesis of the near-UV NH band at 3360 A observed at high resolution with various telescopes. We found that (N/Fe) scales with that of iron in the metallicity range −3.1 < (Fe/H) < 0 with the slope 0.01 ± 0.02. Furthermore, we derive uniform and accurate (N/O) ratios using oxygen abundances from near-UV OH lines obtained in our previous studies. We find that a primary component of nitrogen is required to explain the observations. The NH lines are discovered in the VLT/UVES spectra of the very metal-poor subdwarfs G64-12 and LP815-43 indicating that these stars are N rich. The results are compared with theoretical models and observations of extragalactic H II regions and Damped Lyα systems. This is the first direct comparison of the (N/O) ratios in these objects with those in Galactic stars.