Magnetic fields and stellar spots can alter the equivalent widths of absorption lines in stellar spectra, varying during the activity cycle. This also influences the information that we derive through spectroscopic analysis. In this study we analyse high-resolution spectra of 211 Sun-like stars observed at different phases of their activity cycles, in order to investigate how stellar activity affects the spectroscopic determination of stellar parameters and chemical abundances. We observe that equivalent widths of lines can increase as a function of the activity index log R$^\prime_{\rm HK}$ during the stellar cycle, which also produces an artificial growth of the stellar microturbulence and a decrease in effective temperature and metallicity. This effect is visible for stars with activity indexes log R$^\prime_{\rm HK}$$\geq$$-$5.0 (i.e., younger than 4-5 Gyr) and it is more significant at higher activity levels. These results have fundamental implications on several topics in astrophysics that are discussed in the paper, including stellar nucleosynthesis, chemical tagging, the study of Galactic chemical evolution, chemically anomalous stars, the structure of the Milky Way disk, stellar formation rates, photoevaporation of circumstellar disks, and planet hunting.

中文翻译：

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磁活动如何改变我们从恒星光谱中学到的东西

磁场和星点可以改变恒星光谱中吸收线的等效宽度，在活动周期中会发生变化。这也会影响我们通过光谱分析得出的信息。在这项研究中，我们分析了在其活动周期的不同阶段观察到的 211 颗类太阳恒星的高分辨率光谱，以研究恒星活动如何影响恒星参数和化学丰度的光谱测定。我们观察到，在恒星周期期间，线的等效宽度可以作为活动指数 log R$^\prime_{\rm HK}$ 的函数增加，这也会导致恒星微湍流的人为增长和有效温度的降低和金属性。对于活动指数日志为 R$^\prime_{\rm HK}$$\geq$$-$5.0（即，小于 4-5 Gyr），并且在较高的活动水平上更为显着。这些结果对论文中讨论的天体物理学中的几个主题具有根本意义，包括恒星核合成、化学标记、银河化学演化研究、化学异常恒星、银河系盘的结构、恒星形成率、恒星周围的光蒸发。磁盘和行星狩猎。