抄録
It has been well known that the isotopic ratios of the elements in our solar system are very uniform unless there is any special reason such as radioactive decay, cosmic ray spallation, fractionation effect etc. This suggests that all material had been vaporized and well mixed at an early stage of the formation of our solar system, which is the so-called “isotope mixing”. All the material had lost their past memories at this stage. However, some material survived during the vaporization at the early stage of the solar system. We can detect this material by measuring the isotopic composition that is different from the value in our solar system matters (isotopic anomaly). This material preserves the memory before the formation of our solar system, and is called “presolar grain” or “star dust”. These materials are found to be diamond, silicon carbide, and graphite etc., almost all of which were initially isolated by chemical treatment of meteorite by using the isotope anomaly of noble gases as a guide. Here, I briefly introduce isotopic anomalies of noble gases (Ne-E, Xe-HL, Xe-S, Kr-S) and their host phases.
