Cyanopolyynes are a class of molecules that are out of this world. No, really — these molecules do not exist naturally on present-day Earth.
Cyanopolyynes are long chains of carbon atoms with a hydrogen atom on one end and a nitrogen atom on the other. Interstellar cyanopolyynes are interesting because they might help us better understand the carbon chemistry around stars and how larger carbon molecules, such as those that make up interstellar dust grains and soot, are formed and destroyed during stellar evolution.
Observations with the Green Bank Telescope (GBT) in West Virginia have revealed another interstellar cyanopolyyne - cyanodecapentayne (pronounced sigh-ann-oh-deck-uh-pent-uh-ine), or HC11N - in the Taurus Molecular Cloud, about 430 light years from Earth. This discovery was reported in the February 2021 issue of Nature Astronomy, but the saga of detecting this molecule goes back to the late 1970s.
Predictions for HC11N’s observable chemical signature were reported in 1978. Throughout the 1980s and 1990s, there were multiple detections of HC11N around a cool star and in the Taurus Molecular Cloud, but more recent observations taken toward that same cloud came up empty. This suggested that the earlier reports were based on a mistake made in the assumptions of the molecule’s chemical signature. After more than 20 years, HC11N was knocked off the list of detected molecules, until this latest discovery.
Long carbon chains up to HC17N have been detected in the lab, so there might be even longer carbon chain molecules hiding in the clouds of interstellar space. The bigger question is: will we be able to detect them?