2023 年 57 巻 1 号 p. 1-12
Ca–Al-rich inclusions (CAIs) in meteorites are the oldest objects formed in the Solar System. CAIs are considered to have had complex thermal histories in the solar protoplanetary disk; they formed by condensation and multiple melting and crystallization. Here, I summarize recent progresses of Al–Mg chronological study of CAIs and its problems.