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We present the discovery of a super lithium-rich K giant star, G0928+73.2600.This red giant (T_eff = 4885 K and log g = 2.65) is a fast rotator with aprojected rotational velocity of 8.4 km/s and an unusually high lithiumabundance of A(Li) = 3.30 dex. Although the lack of a measured parallaxprecludes knowing the exact evolutionary phase, an isochrone-derived estimateof its luminosity places the star on the Hertzsprung-Russell diagram in alocation that is not consistent with either the red bump on the first ascent ofthe red giant branch or with the second ascent on the asymptotic giant branch,the two evolutionary stages where lithium-rich giant stars tend to cluster.Thus, even among the already unusual group of lithium-rich giant stars,G0928+73.2600 is peculiar. Using 12C/13C as a tracer for mixing---more mixingleads to lower 12C/13C---we find 12C/13C = 28, which is near the expected valuefor standard first dredge-up mixing. We can therefore conclude that "extra"deep mixing has not occurred. Regardless of the ambiguity of the evolutionarystage, the extremely large lithium abundance and the rotational velocity ofthis star are unusual, and we speculate that G0928+73.2600 has been enriched inboth lithium and angular momentum from a sub-stellar companion.

The Super Lithium-Rich Red Giant Rapid Rotator G0928+73.2600: A Case for Planet Accretion?