Neon isotopes in individual presolar low-density graphite grains from the Orgueil meteorite.

ABSTRACT: We present He and Ne isotopes of individual presolar graphite grains from a low-density separate from Orgueil. Two grain mounts were analyzed with the same techniques but in a different sequence: The first one was measured with NanoSIMS followed by noble gas mass spectrometry, and the second one in reverse order. No grain contained ⁴He and only one grain on the second mount contained ³He. On the first mount, the grains had been extensively sputtered with NanoSIMS ion beams prior to noble gas analysis; we found only one grain out of 15 with presolar ²²Ne above detection limit. In contrast, we found presolar ²²Ne in six out of seven grains on the second mount that was not exposed to an ion beam prior to noble gas analysis. All 22 grains on the two

SUBMITTER: Heck PR 

PROVIDER: S-EPMC6398952 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature