From equivalent widths of the S i lines at 8694 Å , Israelian & Rebolo ( 2001 ) and Takada-Hidai et al .
( 2002 ) have derived a surprisingly high sulphur-to-iron ratio ( [ S/Fe ] \simeq 0.5 to 0.7 ) in six halo stars with [ Fe/H ] \simeq - 2.0 suggesting perhaps that hypernovae made a significant contribution to the formation of elements in the early Galaxy .
To investigate this problem we have used high-resolution spectra obtained with the ESO VLT/UVES spectrograph to determine the S/Fe ratio in 19 main-sequence and subgiant stars ranging in [ Fe/H ] from -3.2 to -0.7 .
The sulphur abundances are determined from S i lines at 8694 Å \em and 9212 - 9237 Å , and the iron abundances from about 20 Fe ii lines .
S/Fe ratios as derived from 1D model atmospheres are presented and possible 3D effects are discussed .
The initial results from our survey do not confirm the high values of [ S/Fe ] quoted above ; instead we find that the ratio [ S/Fe ] remains constant at about 0.35 dex for metallicities -3 < \mbox { [ Fe / H ] } < -1 .