TRACERS OF CHROMOSPHERIC STRUCTURE. I. Ca ii H&K EMISSION DISTRIBUTION OF 13,000 F, G, AND K STARS IN SDSS DR7 SPECTROSCOPIC SAMPLE
TRACERS OF CHROMOSPHERIC STRUCTURE. I. Ca ii H&K EMISSION DISTRIBUTION OF 13,000 F, G, AND K STARS IN SDSS DR7 SPECTROSCOPIC SAMPLE
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DOI：
10.1088/0004-6256/145/5/140
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发表时间：
2013-04
期刊：
影响因子：
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通讯作者：
J. Zhao;T. Oswalt;G. Zhao;Q. H. Lu;A. Luo;L. Zhang
中科院分区：
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作者：
J. Zhao;T. Oswalt;G. Zhao;Q. H. Lu;A. Luo;L. Zhang
我们在斯隆数字巡天（SDSS）数据发布7（DR7）光谱样本中提供了超过13，000颗具有高信噪比（>60）光谱的F，G和K盘星的色球活动指数SHK测量。参数δS被定义为SHK与几颗最不活跃的恒星拟合的“零”发射线之差。次巨星的SHK指数往往比矮星低得多，这提供了一种方法来区分相对低分辨率光谱的矮星和巨星。较冷的恒星通常比较热的恒星更活跃，并显示出更大的散射。与厚盘相关的恒星通常不如薄盘的活跃。K矮星中的活跃滴在银河平面的垂直距离上所占的比例。在这个样本中，金属丰度对F、G和K矮星SHK测量的影响不同。使用疏散星团NGC 2420、M67和NGC 6791作为校准，SDSS样本中大多数恒星的年龄在3到8 Gyr之间。
We present chromospheric activity index SHK measurements for over 13,000 F, G, and K disk stars with high signal-to-noise ratio (>60) spectra in the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) spectroscopic sample. A parameter δS is defined as the difference between SHK and a “zero” emission line fitted by several of the most inactive stars. The SHK indices of subgiant stars tend to be much lower than dwarfs, which provide a way to distinguish dwarfs and giants with relatively low-resolution spectra. Cooler stars are generally more active and display a larger scatter than hotter stars. Stars associated with the thick disk are in general less active than those of the thin disk. The fraction of K dwarfs that are active drops with vertical distance from the Galactic plane. Metallicity affects SHK measurements differently among F, G, and K dwarfs in this sample. Using the open clusters NGC 2420, M67, and NGC 6791 as calibrations, ages of most field stars in this SDSS sample range from 3 to 8 Gyr.