ALMA Reveals Comets Forge Molecules in Their Ghostly Atmospheres

Scientists have learned a bit more about the ghostly atmospheres surrounding comets. Using the Atacama Large Millimeter/submillimeter Array (ALMA), they've managed to make 3D images of the atmospheres surrounding both ISON and Lemmon.

Comets contain some of the oldest materials to be found in our solar system. This means that by understanding their chemistry, researchers can learn a bit more about the births of planets and other planetary bodies.

"We achieved truly first-of-a-kind mapping of important molecules that help us understand the nature of comets," said Martin Cordiner, one of the researchers, in a news release.

With ALMA, the researchers created images of the comets with high-resolution spectra from three organic molecules-hydrogen cyanide (HCN), hydrogen isocyanide (HNC), and formaldehyde (H2CO).These spectra were taken at every point in each image.

So what did they find? It turns out that HCN gas flows outward from the nucleus evenly in all directions. In contrast, HNC is concentrated in clumps and jets which move into different regions of the cometary comas on day-to-day and even hour-to-hour basis. In addition, these distinctive patterns confirm that the HNC and H2CO molecules actually form within the coma; the findings also reveal that HNC may be produced by the breakdown of large molecules or organic dust.

"Understanding organic dust is important, because such materials are more resistant to destruction during atmospheric entry, and some could have been delivered intact to the early Earth, thereby fueling the emergence of life," said Michael Mumma, co-author of the new study. "These observations open a new window on this poorly known window of cometary organics."

The findings reveal a bit more about these comets and allow scientists to learn a bit more about how these cosmic bodies are structured. This, in turn, could tell them a bit more about the materials that constructed our early universe.

The findings are published in The Astrophysical Journal.