Professor Mike Barlow with the Department of Physics and Astronomy at University College London and his team from the European Space Agency's Herschel Space Observatory announced the first discovery of noble gas in the known universe outside of Earth in the Dec. 12, 2013, issue of the journal Science.
Argon gas does not react with other elements at normal temperatures. The temperatures necessary to form an ionized hydride gas were produced by the star that went supernova and formed the Crab Nebula. Energy from the neutron star at the heart of the nebula appears to have ionized the argon, which then joined with molecules of hydrogen to form the molecular ion argon hydride (ArH+). The isotope of argon that formed the argon hydride ion was determined to be argon-36 by spectroscopic measurement and confirmed by rotational frequency correlation with known isotopes and compounds.
Argon-40 is the dominant isotope form of argon on Earth and is known to decay to argon-36. The environment of a supernova is now considered to be preferential for the formation of argon-36.
This is the first time any noble gas or any noble gas compound has ever been definitely observed in an environment outside of Earth.