AI 中文总结
本研究通过ATLAS9合成光谱与HARPS观测，发现B指数对金属丰度敏感度极低，可作为恒星光谱分类等研究的有效工具。
AI 中文摘要
分子吸收特征是晚型恒星大气的重要诊断工具，其中氧化钛（TiO）波段是有效温度和磁活动的敏感示踪剂。近红外TiO指数已得到广泛应用，而可见光波段诊断则为恒星分类和参数估计提供了补充约束。本研究通过ATLAS9生成的合成光谱与HARPS光谱仪的高分辨率观测，探究以567 nm为中心的TiO吸收量度B指数的金属丰度依赖性。合成网格覆盖有效温度3500-4000 K、金属丰度[Fe/H]从-4到+0.2的范围，观测样本包含23颗MK光谱型、有效温度3500-4000 K的恒星。理论与经验分析均表明，B指数对恒星金属丰度的敏感度可忽略不计，仅检测到微弱相关性，因此计算B指数时无需纳入金属丰度相关项。B指数对金属丰度的低敏感性，进一步强化了其作为光谱分类、恒星大气建模及磁活动恒星研究有效工具的实用性。
英文摘要
Molecular absorption features constitute essential diagnostics of late-type stellar atmospheres, with titanium oxide (TiO) bands serving as sensitive tracers of effective temperature and magnetic activity. While near-infrared TiO indices are well established, visible-band diagnostics provide complementary constraints for stellar classification and parameter estimation. This study investigates the metallicity dependence of the B-index, a TiO absorption measure centered at 567 nm, through synthetic spectra generated with ATLAS9 and high-resolution observations from the HARPS spectrograph. The synthetic grid spans effective temperatures between 3500-4000 K and metallicities from [Fe/H] =-4 to +0.2, while the observational sample comprises 23 MK spectral types stars with effective temperatures between 3500-4000 K. Both theoretical and empirical analyses demonstrate that the B-index exhibits negligible sensitivity to stellar metallicity, with only marginal correlations detected. Therefore, there is no requirement to include this feature in the calculation of the B-index. The B-index's low sensitivity to metallicity reinforces its utility as an effective tool for spectral classification, stellar atmosphere modeling, and the study of magnetically active stars.
Comments14 pages, 5 figures
Journal refAstrophysics and Space Science, 2026
