... Sharpless 212 in Hydrogen and Sulfur . ... Observational evidence indicates that the outskirts of developing open clusters of stars are primary locations. Pictured above is one such open cluster: Sharpless 212. ... The energetic light from these stars ionizes surrounding hydrogen atoms creating an HII region . ... Sharpless 212 also contains small amounts of dust and heavy atoms such as Sulfur . ... Sharpless 212 spans about 20 light years and lies about 25,000 light years away. ...