Aluminium abundance in metal-deficient stars

The explosive carbon burning theory studied by Arnett predicts an overdeficiency of Al relative to Mg in metal-poor stars. Analyses of such stars by Peterson have shown a good agreement with Arnett's theory. But other measurements of Al abundance on six cool metal-poor stars (Spite have not shown any significant deficiency. All the studies of aluminium abundance have been made up to now using the resonance lines of aluminium at 3,944 and 3,961 A which however suffer large uncertainties. Owing to the improvement of the receptors in the red, we have obtained high quality spectra (high resolution, good S/N ratio) in the region of the weak lines of aluminium at 6,696 and 6,698 A for six metal-poor stars. The abundances of Al derived from these lines are very reliable; they do not show Al overdeficiency. According to Arnett's theory, the synthesis of light metals by carbon burning has not taken place in explosive conditions