3He/4He in Stardust Samples

Document Type

Conference Abstract

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Physics and Astronomy


The presence of excess 3He, which cannot result from air contamination, is strong evidence that indigenous noble gases exist in Stardust samples. The 3He/4He ratio can in principle point to when comets acquired their noble gases, and from what volatile reservoir —the early protosolar nebula, near the evolving sun during or just after the deuterium burning that elevated the level of protosolar 3He, or by later implantation of solar-wind-like radiation. Jupiter’s 3He/4He ratio of 1.66 x 10-4 (Mahaffy et al., 1998) likely reflects the protosolar value. 3He/4He is ~3.6 x 10-4 in the sun after deuterium burning (Geiss et al., 2004), and 4.82 x 10-4 in the solar wind (Heber et al., 2007). Our preliminary measured ratio of ~2.7 ± 0.3 x 10-4 falls between the protosolar and solar D-burning values.

Presented at the 17th Annual V.M. Goldschmidt Conference (Cologne, Germany). .