Yurimoto Hisayoshi, Kuramoto Kiyoshi
Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan.
Science. 2004 Sep 17;305(5691):1763-6. doi: 10.1126/science.1100989.
Meteorites and their components have anomalous oxygen isotopic compositions characterized by large variations in 18O/16O and 17O/16O ratios. On the basis of recent observations of star-forming regions and models of accreting protoplanetary disks, we suggest that these variations may originate in a parent molecular cloud by ultraviolet photodissociation processes. Materials with anomalous isotopic compositions were then transported into the solar nebula by icy dust grains during the collapse of the cloud. The icy dust grains drifted toward the Sun in the disk, and their subsequent evaporation resulted in the 17O- and 18O-enrichment of the inner disk gas.
陨石及其成分具有异常的氧同位素组成，其特征是18O/16O和17O/16O比值存在巨大变化。基于最近对恒星形成区域的观测以及吸积原行星盘的模型，我们认为这些变化可能源于母分子云通过紫外光解离过程。在云坍缩期间，具有异常同位素组成的物质随后由冰质尘埃颗粒被输送到太阳星云。冰质尘埃颗粒在盘中向太阳漂移，其随后的蒸发导致内盘气体的17O和18O富集。
