Infrared Echelle Spectroscopy of Palomar 6 and M71
Infrared Echelle Spectroscopy of Palomar 6 and M71
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Palomar 6 和 M71 的红外阶梯光谱
DOI：
10.1086/425047
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
S. Balachandran
中科院分区：
文献类型：
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作者：
Jae;B. Carney;S. Balachandran
我们提出了高分辨率红外阶梯光谱的球状星团帕洛玛6和M71。我们观测到的1996年日心径向速度平均值为+180.6 ± 3.2 km s-1，比Minniti在1995年发现的低20 km s-1。与之前使用低分辨率光谱进行的金属丰度估计相反，我们的结果表明，M76具有中等金属丰度，[Fe/H]=-1.0 ± 0.1，并且比M71略贫金属。合理改变模型大气的表面温度或微湍流速度，在± 0.2 dex以上不会影响[Fe/H]。尽管它的金属丰度很高，但根据单个星系团成员的光谱，[Si/Fe]和[Ti/Fe]比值似乎分别增加了0.4和0.5 dex，这表明银河系内晕可能经历了一个非常快速的化学富集历史。
We present high-resolution infrared echelle spectroscopy for the globular clusters Palomar 6 and M71. Our mean heliocentric radial velocity of Pal 6 is +180.6 ± 3.2 km s-1 and is 20 km s-1 lower than that found by Minniti in 1995. Contrary to the previous metallicity estimates using low-resolution spectroscopy, our results show that Pal 6 has an intermediate metallicity, with [Fe/H] = -1.0 ± 0.1, and is slightly more metal poor than M71. Reasonable changes in the surface temperature or the microturbulent velocity of the model atmospheres do not affect [Fe/H] at more than ±0.2 dex. In spite of its high metallicity, on the basis of the spectrum of a single cluster member the [Si/Fe] and [Ti/Fe] ratios of Pal 6 appear to be enhanced by 0.4 and 0.5 dex, respectively, suggesting that the Galactic inner halo may have experienced a very rapid chemical enrichment history.