Gases trapped in presolar diamond HL, P3 and P6 components

There are indications that the noble gases were introduced into the nanodiamonds by ion implantation. Among other things, they do not contain excessive abundances of Xe 

A °Xe-free composition for the HL astrophysical scenarios. Since relative excesses in Xe and nor are the relative excesses of the two r-only isotopes ( Xe and Xe), the nucleosynthetic sources cannot be the p- and r-processes proper. Two explanations which are currently debated for the heavy (the H) part of Xenon-HL involve a neutron burst intermediate between s- and r-process (Howard et al. 1992 Meyer et al. 2000) and a regular r-process augmented by separation of stable Xe isotopes and radioactive precursors on a short time scale after the explosion of a supernova (Ott 1996 Richter et al. 1998). 

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