Organic Matter that Could be Created Naturally by Stars

Researchers at the University of Hong Kong observed stars at different evolutionary phases and found that they are able to produce complex organic compounds and eject them into space, filling the regions between stars. According to study’s lead author Sun Kwok, of the University of Hong Kong, the compounds are so complex that their chemical structures resemble the makeup of coal and petroleum. Such chemical complexity was thought to arise only from living organisms, but the results of the new study show that these organic compounds can be created in space even when no life forms are present. In fact, such complex organics could be produced naturally by stars, and at an extremely rapid pace. 

Researchers studied a set of well-known but mysterious infrared emissions found in stars, interstellar space and galaxies. These phenomena, which are collectively called Unidentified Infrared Emission (UIE) features, have been known for 30 years, but the exact source of the emissions has not been pinned down, and remains a broad assumption. Kwok and Zhang analyzed data from the European Space Agency’s Infrared Space Observatory and NASA’s Spitzer Space Telescope to show that the Unidentified Infrared Emission features are not emitted by PAH molecules because the emissions have chemical structures that are far more complex. They found that characteristics of the Unidentified Infrared Emission features could not be detected in low to medium mass stars. But, the astronomers found that the emissions began to appear in stars in the protoplanetary nebula stage and grew stronger as the stars matured into the planetary nebula phase. Another surprising thing they found was just how quickly stars were generating complex organic compounds and ejecting the dusty material into their surrounding environment. The researchers also studied emissions from exploding stars and found that these dynamic cosmic events produced dust even more rapidly. Further research in this area will be necessary, and Kwok intends to continue analyzing additional infrared observations to better pin down the chemical structure of organic star dust. He is also interested in studying more about how and why stars are able to produce complex organics as quickly as they seem to.