Overview

• A peer-reviewed Nature Communications study models octasulfur crowns and polysulfanes on icy dust grains as hidden sulfur reservoirs in dense molecular clouds.
• Laboratory simulations and quantum-chemical calculations show these solid-phase sulfur compounds are stable at cryogenic temperatures and invisible to gas-phase spectroscopy.
• This sequestration mechanism explains why gas-phase sulfur appears depleted by roughly three orders of magnitude compared with theoretical abundances.
• The authors call for targeted radio-telescope observations of polysulfanes once they sublimate into the gas phase in star-forming regions to validate their proposal.
• No direct astronomical detections of these sulfur-bearing ice species have yet been made, making focused radio searches the crucial next step.