SPREAD OF THE LITHIUM ABUNDANCE IN HALO STARS

The observed scatter of the lithium abundance around a ''plateau'' is revisited for three samples of stars for which the temperature has bee n determined from either the excitation temperature, or the dereddened color (b - y)(o) or the profile of the H-alpha wings. Systematic diff erences are noted between tween the three methods of temperature deter mination. From sample to sample the rms observed scatter of the lithiu m abundance varies from 0.06dex to 0.08dex (to be compared to the valu e 0.13 previously found by Thorburn (1994), for another sample of star s). We show that in all cases but one, this scatter is fully explained by the temperature and equivalent width errors. The intrinsic scatter , if real, is small.