Abundances on the main sequence of ω Centauri

Abundance ratios of carbon, nitrogen, and strontium relative to iron, calculated using spectrum synthesis techniques, are given for a sample of main-sequence and turnoff stars that belong to the globular cluster ω Centauri. The variations of carbon, nitrogen, and/or strontium show several different abundance patterns as a function of [Fe/H]. The source of the enhancements/depletions in carbon, nitrogen, and/or strontium may be enrichment from asymptotic giant branch stars of low (1-3 M_⊙) and intermediate (3-8 M_⊙) mass. Massive rotating stars that produce excess nitrogen without carbon and oxygen overabundances may also play a role. These abundances enable different contributors to be considered and incorporated into the evolutionary picture of ω Cen.