摘要

New infrared absorption measurements of oxygen isotope ratios in CO gas from individual young stellar objects confirm that the solar system is anomalously high in its [O-18]/[O-17] ratio compared with extrasolar oxygen in the Galaxy. We show that this difference in oxygen isotope ratios is best explained by similar to 1% enrichment of the protosolar molecular cloud by ejecta from Type II supernovae from a cluster having of order a few hundred stars that predated the Sun by at least 10-20 Myr. The likely source of exogenous oxygen was the explosion of one or more B stars during a process of propagating star formation.

  • 出版日期2011-3-1

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