For nine bright K giants within 100 pc of the sun, the fundamental parameters and the non‐local thermodynamic equilibrium (LTE) abundances of three key light elements (Li, C, and O) are accurately determined. These stars are of special interest due to the planets detected around them. Their fundamental parameters are found to be typical for K giants; in particular, these stars have effective temperatures T_eff = 3,920–4,830 K, surface gravities log g = 1.20–2.85, masses M = 1.2–2.8 M_⊙, and ages t = 0.4–5.4 Gyr (the pronounced anticorrelation between ages t and masses M exists). The microturbulent parameter V_t derived from Fe I lines varies between 1.2 and 1.9 km s⁻¹; the metallicity index [Fe/H] forfive stars is close to the normal (zero) value, for other four stars it varies between −0.3 and −0.4 dex. All the giants are on the red giant branch stage and passed the first‐dredge‐up (FDU) phase. This conclusion is confirmed by the published low isotope ratios ¹²C/¹³C and ¹⁶O/¹⁷O. Basing on the non‐LTE analysis of Li I, C I, and O I lines, we determined abundances of lithium, carbon, and oxygen, three tracers of stellar evolution. The carbon deficiency −0.3 dex is found for the giants, which is quite expectable for these post‐FDU objects. The oxygen abundance is likely to be unchanged, whereas for the C/O ratio we obtained (after correction due to galactic chemical evolution) the mean value [C/O]_cor = −0.22 ± 0.10 that is in very good agreement with the theory. The lithium abundance is not detected for seven of nine program giants; this result is quite expectable for the post‐FDU stars. We determined the Li abundance with the confidence only for two giants, namely, log ϵ(Li) = 0.92 for β Gem and log ϵ(Li) = 0.45 for μ Leo; this result contradicts the standard theory. Hypothetical engulfment by a star of a giant planet could solve the problem.

中文翻译：

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九个明亮和邻近的K巨人的关键轻元素的基本参数和非局部热力学平衡丰度

对于在太阳100 pc之内的九个明亮的K巨人，可以精确确定三个关键轻元素（Li，C和O）的基本参数和非局部热力学平衡（LTE）丰度。由于在它们周围发现了行星，因此特别关注这些恒星。他们的基本参数被发现是K巨人的典型特征。特别是，这些分具有有效温度Ť _EFF  = 3,920-4,830 K，表面比重登录克 = 1.20-2.85，群众中号 = 1.2-2.8 中号_⊙，和年龄吨 = 0.4-5.4 Gyr的（年龄之间的反相关明显吨和质量M存在）。微湍流参数V来自Fe I线的_t在1.2至1.9 km s ^-1之间变化; 五颗星的金属度指数[Fe / H]接近正常值（零），其他四颗星的金属度指数[-Fe / H]在-0.3到-0.4 dex之间变化。所有的巨人都处于红色巨人分支阶段，并通过了第一疏通（FDU）阶段。公布的低同位素比¹² C / ¹³ C和¹⁶ O / ¹⁷证实了这一结论。O.基于对Li I，CI和OI谱线的非LTE分析，我们确定了锂，碳和氧的丰度，这是三个恒星演化的示踪剂。巨人发现碳缺乏量为-0.3 dex，这对于这些FDU后的物体来说是可以预料的。氧丰度可能不会发生变化，而对于C / O比，我们得到的（由于银河化学放出而进行校正后）的平均值[C / O] _cor  = -0.22±0.10，与理论值非常吻合。9个程序巨人中有7个未检测到锂丰度。对于后FDU明星来说，这个结果是可以预期的。我们确定了李丰的信心只为两大巨头，即登录ε（李）= 0.92，β宝石和日志ε对于μLeo，（Li）= 0.45 ; 这个结果与标准理论相矛盾。假设一颗巨大行星的恒星吞没可以解决这个问题。