Host: Abstracts of Annual Meeting of the Geochemical Society of Japan
Pages 199-
The model for early solar irradiation from young Sun has long been suggested, but is somehow model-depending and still disputable. Isotopic evidence of excess 10B decayed from 10Be in Calcium-Aluminum-rich inclusions (CAIs) and astronomical observations of intensive X-ray emissions from stellar analogues of the young Sun suggest that a fraction of the early solar materials were intensively irradiated by the young Sun. For further quantitative discussion about the early solar irradiation models, the possible occurrence of chemical fractionation of volatile elements including spallogenic B and Li during or after irradiation has been pointed out. In order to dissolve this issue, 138La has been chosen to be an adequate isotopic tracer as one of refractory and spallogenic products caused by solar irradiation. Finding of spallogenic 138La may provide isotopic constraints on the early solar irradiation models.
