Search of intersteller media and the evolution to planetary matters.

原始陨石中的星际介质只是阐明太阳系前历史的线索。星际介质和太阳物质之间的区别仅仅是元素的同位素比率。我们对原始陨石中单个细小颗粒的同位素比值、结构、形状和晶体结构进行了原位测量。这项研究的目标是构建从星际介质到行星物质的物质演化的新场景。利用二次离子质谱仪建立了一种新的氧同位素比值的微观尺度分析方法。对阿连德陨石中的富钙铝包裹体(CaI)进行了分析，发现其含有氧同位素组成极高的黄长石晶体(相对于陆地氧-16，富氧-16为-5%)。矿物(黄长石、尖晶石和方沸石)的氧同位素变化表明，CaI的结晶始于可能是太阳星云中液滴的富氧物质，与周围贫氧星云气体的氧同位素交换是通过CaI的结晶进行的。此外，在随后的太阳星云重新加热事件中还发生了氧同位素交换。从CaI形成时期到球粒形成时期，富160个尘埃和160个贫气体在太阳星云中持续存在。新证据的一个可能场景是具有两极外流的活跃原星。原太阳系附近的星际介质已经过热处理，然后发射到外太阳系。因此，在太阳系演化的第一个百万年里，太阳星云的组成沿径向不均匀地分布，得到了每颗行星的组成和同位素比值的特征。

Interstellar media in primitive meteorites are only clue to clarify presolar history. The difference between interstellar media and solar matters is only isotope ratio of elements. We have made in-situ measurements of isotope ratios, textures, shapes and crystal structures for individual fine particles in primitive meteorites. The goal of in this study is construction of new scenario for material evolution from interstellar media to planetary matters.A novel micro-scale analysis for oxygen isotope ratios has been developed by secondary ion mass spectrometry. A calcium-aluminum-rich inclusion (CAI) from the Allende meteorite was analyzed and found to contain melilite crystals with extreme oxygen-isotope compositions (-5 percent oxygen-16 enrichment relative to terrestrial oxygen-16). The oxygen isotopic variation measured among the minerals (melilite, spinel, and fassaite) indicates that crystallization of the CAI started from oxygen-16-rich materials that were probably liquid droplets in the solar nebula, and oxygen isotope exchange with the surrounding oxygen-16-poor nebular gas progressed through the crystallization of the CAI.Additional oxygen isotope exchange also occurred during subsequent reheating events in the solar nebula. The 160-rich dust and 160-poor gas continued together in the solar nebula from the CAI-forming period until the chondrule-forming period.A possible scenario for new evidence would be an active protosun with bipolar out-flow. Interstellar media near the protosun has been processed thermally and then launched into outer solar system. Therefore, composition of solar nebulae distributed heterogeneously along radial direction, The characteristics of composition and isotope ratio of each planet have been achieved in the first million years of solar system evolution.