ABSTRACT
Analysis of high-resolution spectra of stars in NGC 288 confirm a high overall metal abundance for this cluster, [Fe/H] = -1.0 ± 0.2, as well as an excess of oxygen relative to iron, [O/Fe] = +0.4. A deficiency of ZCNO or oxygen cannot explain the anomalous blue horizontal branch of this cluster, nor can excessive mass loss on the upper giant branch. A high helium abundance or rotation-induced mixing remain as possible alternatives.