Astrophysicists crack the case of 'disappearing' sulfur in planetary nebulae

Two astrophysicists from the Laboratory for Space Research (LSR) at the University of Hong Kong (HKU) have finally solved a 20-year-old astrophysical puzzle concerning the lower-than-expected amounts of the element sulfur found in planetary nebulae (PNe) in comparison to expectations and measurements of other elements and other types of astrophysical objects.