Detection of a Noble Gas Molecular Ion, 36ArH+, in the Crab Nebula
Publication date: 13 December 2013
Authors: Barlow, M. et al.
Noble gas molecules have not hitherto been detected in space. From spectra obtained with the Herschel Space Observatory, we report the detection of emission in the 617.5- and 1234.6-gigahertz J=1-0 and 2-1 rotational lines of 36ArH+ at several positions in the Crab Nebula, a supernova remnant known to contain both molecular hydrogen and regions of enhanced ionized argon emission. Argon-36 is believed to have originated from explosive nucleosynthesis in massive stars during core-collapse supernova events. Its detection in the Crab Nebula, the product of such a supernova event, confirms this expectation. The likely excitation mechanism for the observed 36Ar emission lines is electron collisions in partially ionized regions with electron densities of a few hundred per centimeter cubed.Link to publication