We present here the first measurements of sulphur abundances in extragalactic stars .
We make use of high resolution spectra , obtained with UVES at the ESO 8.2 m Kueyen telescope , of three giants of the Globular Cluster Terzan 7 , which belongs to the Sagittarius dwarf galaxy .
We measure the sulphur abundances using the lines of S i multiplet 1 .
The S/Fe ratios for all three stars are nearly solar , thus considerably lower than what is found in Galactic stars of comparable iron content ( [ Fe/H ] \sim - 0.50 ) .
This finding is in keeping with the abundances of other \alpha -chain elements in this cluster and in Sagittarius and other dSphs in general .
These low \alpha -chain elements to iron ratios suggest that Sagittarius and its Globular Clusters have experienced a low or bursting star-formation rate .
Our sulphur abundances imply \langle \log ( S / O ) \rangle = -1.61 which is comparable to what is found in many H ii regions of similar oxygen content , and is slightly lower than the solar value ( log ( S/O ) ☉ = -1.51 ) .
These are also the first measurements of sulphur abundances in a Globular Cluster , thus a direct comparison of Terzan 7 and Galactic Globular Clusters is not possible yet .
However our analysis suggests that the lines of S i multiplet 1 should be measurable for other Globular Clusters at least down to a metallicity \sim - 1.5 .