南方恒星的金属性和活动
Metallicities & Activities of Southern Stars
摘要：
我们提出了高分辨率光谱测量的结果，以确定在南半球明亮的恒星的金属丰度和活动。我们测量了353颗V=7.5-9.5的太阳型恒星的铁丰度（[Fe/H]）和色球发射指数（logR'HK）。[Fe在库鲁茨模型大气的大网格中，使用自定义的卡方拟合程序确定[2 H]丰度。色球活动是通过测量强CaII HK线核心的发射量来确定的。金属丰度样品与其他[Fe/H]测定结果进行了比较，发现光谱值在+/-0.05 dex水平，光度值在+/-0.1 dex水平与这些结果一致。色球活动的分布符合双峰分布，与其他工作的结论一致。此外，还试图对蒙德极小期的状态进行分析，发现样本中有6+/-4颗恒星可能处于蒙德极小期的演化阶段，因此太阳应该只在蒙德极小期度过其主序星寿命的百分之几。
英文摘要：
We present the results from high-resolution spectroscopic measurements to determine metallicities and activities of bright stars in the southern hemisphere. We have measured the iron abundances ([Fe/H]) and chromospheric emission indices (logR'HK) of 353 solar-type stars with V=7.5-9.5. [Fe/H] abundances are determined using a custom chi^2 fitting procedure within a large grid of Kurucz model atmospheres. The chromospheric activities were determined by measuring the amount of emission in the cores of the strong CaII HK lines. The sample of metallicities has been compared to other [Fe/H] determinations and was found to agree with these at the +/-0.05 dex level for spectroscopic values and at the +/-0.1 dex level for photometric values. The distribution of chromospheric activities is found to be described by a bimodal distribution, agreeing well with the conclusions from other works. Also an analysis of Maunder Minimum status was attempted and it was found that 6+/-4 stars in the sample could be in a Maunder Minimum phase of their evolution and hence the Sun should only spend a few per cent of its main sequence lifetime in Maunder Minimum.
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