Yuki Hibiya

Assistant Professor, Graduate School of Arts and Sciences, The University of Tokyo *Profile is at the time of the award.

2022Inamori Research GrantsScience & Engineering

Research topics
The Birth Environment of the Solar System constrained by Noble Gas Isotopes: Elucidating the Temperature Structure of the Primordial Solar System Disk and the Type of Nearby Star
In order to investigate the origin and evolution of our solar system, it is necessary to chemically elucidate the birth environment of the solar system by focusing on its smallest constituent unit, the nuclide. In this study, I will improve an existing noble gas mass spectrometer to realize an ultra-sensitive noble gas Xe isotope ratio analysis of meteorites to determine the initial abundance of the short-lived nuclide iodine-129 in the solar system. By comparing the results with existing values for other meteorites and the latest nucleosynthesis calculations, I will determine the temperature range of the proto-solar disk and the type of proto-solar neighbor stars.


The most exciting part of space geochemistry research is that we can touch the chemical evolution of about 4.6 billion years ago from a meteorite a few centimeters in size in front of our eyes. Through the research results of this grant, I hope to contribute to the development of space geochemistry and the intellectual property of humankind, and I will continue to make further efforts to convey to people the real thrill of this kind of research.

Outline of Research Achievments

The analysis of noble gas isotopes in meteorites has revealed that, until approximately 50 million years after the formation of the solar system, temperature conditions of several hundred degrees Celsius existed locally or widely in the region outside the Jupiter’s orbit. Furthermore, isotopes with low condensation temperatures were homogeneously distributed in the protoplanetary disk before that, indicating that temperature conditions higher than 800°C were maintained.

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