Mystery Yellow Hypergiant HR 5171 solved
An international team of astronomers, including Alex Lobel, astrophysicist of the Royal Observatory of Belgium, have discovered the origin of mysterious blue light near the Yellow Hypergiant HR 5171A.
The light was accidentally observed in the early 1970ies by a team member, but without providing a good explanation for it. More than 40 years later the team’s research reveals the light was caused by Polycyclic Aromatic Hydrocarbon molecules, or PAHs.
PAHs are ring-shaped molecules. They are observed in large gas clouds in specific conditions between and near stars. On Earth the molecules form by incomplete combustion of fossil fuels. In the Milky Way they are observed in dusty nebulae.
Read more (link NOVA press release)
Image: The bright central star is the yellow hypergiant HR 5171A observed with Spitzer/NASA in infrared light. The Gum48d nebula is an active star formation region.