The forbidden 1082 nm line of sulphur:

Context.Sulphur is an element which is formed in the α-process and is easily measured in the gaseous phase in external galaxies. Since it does not form dust, it is the preferred indicator for α-elements, rather than Si or Mg, for which dust corrections are necessary. The measurement of the sulphur abundance in stars is not an easy task, relying mainly on high excitation lines with non-negligible deviations from LTE. The 1082 nm sulphur forbidden transition is less sensitive to departures from LTE and is less dependent on temperature uncertainties than other sulphur lines usually employed as abundance indicators. Therefore it should provide a more robust abundance diagnostics.