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In this work we present the results of our analysis of 16,300medium-resolution LAMOST spectra of late-type stars in the Kepler field withthe aim of determining the stellar parameters, activity level, lithiumatmospheric content, and binarity. We have used a version of the code ROTFITspecifically developed for these spectra. We provide a catalog with theatmospheric parameters (Teff, log(g), and [Fe/H]), radial velocity (RV), andprojected rotation velocity (vsini). For cool stars (Teff < 6500 K), we alsocalculated the H-alpha and LiI-6708 equivalent width, which are importantindicators of chromospheric activity and evolutionary stage, respectively. Wehave derived the RV and atmospheric parameters for 14,300 spectra of 7443stars. Literature data were used for a quality control of the results. The Teffand log(g) values are in good agreement with the literature. The [Fe/H] valuesappear to be overestimated for metal-poor stars. We propose a relation tocorrect the [Fe/H] values derived with ROTFIT. We were able to identifydouble-lined binaries, stars with variable RVs, lithium-rich giants, andemission-line objects. Based on the H-alpha flux, we found 327 active stars. Wedetected the LiI-6708 line and measure its equivalent width for 1657 stars,both giants and stars on the main sequence. Regarding the latter, we performeda discrete age classification based on the atmospheric lithium abundance andthe upper envelopes of a few open clusters. Among the giants, we found 195Li-rich stars, 161 of which are reported here for the first time. Norelationship is found between stellar rotation and lithium abundance, whichallows us to rule out merger scenarios as the predominant explanation of theenrichment of Li in our sample. The fraction of Li-rich giants, about 4%, ishigher than expected.

Characterization of Kepler targets based on medium-resolution LAMOST spectra analyzed with ROTFIT