Webb Reveals the Chemical Secret of a Distant Galaxy ⚡ экспресс
Observations of the galaxy IRAS 07251-0248 with JWST/NIRSpec and MIRI/MRS in the 3–28 μm range revealed gaseous hydrocarbons: benzene (C6H6), triacetylene (C6H2), diacetylene (C4H2), acetylene (C2H2), methane (CH4), and methyl radical (CH3), along with deep absorption bands of solid-phase amorphous carbon. Their anomalously high concentration indicates a rich hydrocarbon chemistry that cannot be explained by high-temperature gas-phase reactions, ice evaporation, or oxygen deficiency. The most probable source is the destruction of carbonaceous dust grains and PAHs by cosmic rays, supported by a correlation between acetylene (C2H2) abundance and the cosmic-ray ionization rate in other ultraluminous infrared galaxies. The hydrocarbons outflow at ~160 km/s, which may contribute to the formation of hydrogenated amorphous grains. Apparently, IRAS 07251-0248 is not an exception but an extreme manifestation of hydrocarbon chemistry typical of dust-obscured galactic nuclei.
Astronomers using James Webb and spectroscopy (splitting light into colors) peered through dust into the center of galaxy IRAS 07251-0248. There they discovered benzene, acetylene, methane — the same hydrocarbons found in gasoline and plastics. There are hundreds of times more than expected, and hot gas alone can't produce such amounts. The key lies in cosmic dust, rich in carbon. Cosmic rays bombard dust grains, acting like a jackhammer: they knock ready-made molecules out of them.
These molecules leave the core at a speed of 160 kilometers per second and can re-clump into dust of a new composition. Similar chemical factories, hidden behind dust, operate in other galaxies as well, filling the cosmos with organic matter.
🎯 Benzene — a component of gasoline and plastics — has been found for the first time outside our Galaxy; previously it had only been spotted in the Milky Way.