Cosmological Implications of the First Measurement of the Local ISM Abundance of [TSUP]3[/TSUP]He

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Abstract
Deuterium plays a crucial role in testing big bang nucleosynthesis. However, its chemical evolution is intertwined with that of 3He. Gloeckler & Geiss's new measurement of the 3He abundance and the Hubble Space Telescope measurement of D, both in the local ISM today, can be compared to the presolar nebula abundances of D and 3He. Within the uncertainties, the sum of D +3He relative to hydrogen is unchanged. This indicates that over the past 4.5 Gyr there has been at most modest stellar production of 3He, in contradiction with stellar modeling, or modest stellar destruction of 3He, in contradiction with efficient "solar spoons." The constancy of D +3He alleviates some of the cosmic tension between the big bang 4He abundance and those of D and 3He.
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