标题： 昴星团照相光度学：与场星的比较 显示英文标题

标题： Caby Photometry of the Hyades: Comparisons to the Field Stars

摘要： 给出了卡比系统上金牛座星团矮星的中间带测光数据，这些矮星的光谱型从A型到晚期K型不等。利用没有异常大气的单颗恒星构建了一个平均的hk, b-y关系，并将其与太阳邻域的场星进行了比较。 对于F型矮星，金牛座的关系在双色图中定义了一个近似的下限，这与[Fe/H]在+0.10到+0.15之间的值一致。 这些指数-颜色图遵循常见的惯例，即在图表底部显示丰度最高的恒星，尽管富金属恒星的指数值在数值上更大。 对于[Fe/H]在+0.4到-1.0范围内的场F型矮星，[Fe/H]=-5.6Δhk+0.125，没有发现斜率有颜色依赖性的证据。 对于G和K型矮星，金牛座的平均关系在双色图中穿过场星分布，为本地盘星体定义了一个近似的上限。 发现位于金牛座星体之上的恒星至少属于以下三类之一：[Fe/H]低于-0.7，[Fe/H]高于金牛座，或者具有耀斑活动性。 得出结论认为，与模型大气的预测相反，对于给定颜色的冷矮星，hk指数在低于太阳成分的恒星中达到最大值，并且随着[Fe/H]超过某个临界值而下降。 然而，这一趋势与基于狭窄Ca滤波器的合成指数的预测是一致的，在这种情况下，交叉点是由b-y的颜色对金属丰度的敏感性引起的。 显示英文摘要

摘要： Intermediate-band photometry of the Hyades cluster on the Caby system is presented for dwarf stars ranging from spectral type A through late K. A mean hk, b-y relation is constructed using only single stars without anomalous atmospheres and compared to the field stars of the solar neighborhood. For the F dwarfs, the Hyades relation defines an approximate LOWER bound in the two-color diagram, consistent with an [Fe/H] between +0.10 and +0.15. These index-color diagrams follow the common convention of presenting stars with highest abundance at the bottom of the plot although the index values for the metal-rich stars are numerically larger. For field F dwarfs in the range [Fe/H] between +0.4 and -1.0, [Fe/H] = -5.6 delta-hk + 0.125, with no evidence for a color dependence in the slope. For the G and K dwarfs, the Hyades mean relation crosses the field star distribution in the two-color diagram, defining an approximate UPPER bound for the local disk stars. Stars found above the Hyades stars fall in at least one of three categories: [Fe/H] below -0.7, [Fe/H] above that of the Hyades, or chromospherically active. It is concluded that, contrary to the predictions of model atmospheres, the hk index for cool dwarfs at a given color hits a maximum value for stars below solar composition and, with increasing [Fe/H] above some critical value, declines. This trend is consistent, however, with the predictions from synthetic indices based upon much narrower Ca filters where the crossover is caused by the metallicity sensitivity of b-y.