Researchers this week revealed that a rare molecule has been spotted in the Crab Nebula. The molecule, Argon Hydride, was found in data collected by the European Space Agency’s (ESA) Herschel Space Observatory, which ran out of coolant and ended its mission this past summer.. The finding has been published in the journal Science.

Though argon on its own is a common byproduct of supernovae, this discovery is the first time astronomers have found a noble-gas based molecule in space.

“At first, the discovery seemed bizarre,” said Michael Barlow, lead author of the paper and an astronomer at University College London. “With hot gas still expanding at high speeds after the explosion, a supernova remnant is a harsh, hostile environment, and one of the places where we least expected to find a noble-gas based molecule.

“But we soon realised that even in the Crab Nebula, there are places where the conditions are just right for a noble gas to react and combine with other elements.”

Argon hydride is formed from certain molecules of Argon and hydrogen molecules. The argon hydride found in the Crab Nebula was found in the so-called transition regions separating regions where ions form and others where molecules are formed.

Following the discovery, astronomers are planning more research into the Crab Nebula. Specifically, researchers will be searching for other molecules that may be formed from other isotopes of argon.

“This is not only the first detection of a noble-gas based molecule in space, but also a new perspective on the Crab Nebula, said Göran Pilbratt, project scientist for Herschel at ESA. “Herschel has directly measured the argon isotope we expect to be produced via explosive nucleosynthesis in a core-collapse supernova, refining our understanding of the origin of this supernova remnant.”

(Image courtesy ESA/Herschel/PACS/MESS Key Programme Supernova Remnant Team; NASA, ESA and Allison Loll/Jeff Hester (Arizona State University))