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A.C. Fredericks, S.C. Balachandran (Univ. of Maryland)
At 2.4 Gyr, the open cluster IC 4651 is between the ages of the Hyades and M67 where cluster lithium data are sparse. We present lithium, iron and oxygen abundances in a sample of 25 turn-off, giant and sub-giant stars in this cluster derived from high-resolution spectra obtained at CTIO. Temperatures and gravities are determined spectroscopically and compared with photometric estimates. We compare the expected red giant lithium dilution with the observed difference between the turn-off and giant stars to determine the extent of Li destruction in the turn-off stars. The Li 'dip' in IC 4651 is at and slightly below the cluster turn-off. These stars are examined in detail to seek further clues to the cause of this peculiar phenomenon.