Centers & Labs

RIKEN Nishina Center for Accelerator-Based Science

Astro-Glaciology Research Group

Group Director: Yuko Motizuki (D.Sci.)
Yuko  Motizuki(D.Sci.)

Our Astro-Glaciology research unit is engaged in simulating nucleosynthesis in core-collapse supernovae and the impact of astronomical phenomena such as solar proton events and galactic supernovae on the chemical composition of the stratosphere. We also analyze ionic and isotopic concentrations in Antarctic ice cores that preserve the past atmospheric information. By combining these theoretical and experimental studies, we investigate the relationship between solar activity and climate changes in the past, and aim to understand the galactic supernova rate ultimately.

Main Research Field


Related Research Fields

Multidisciplinary / Space Science / Geosciences

Research Subjects

  • Ionic and isotopic analyses of ice cores
  • Radiation process and chemical reactions in the upper atmosphere induced by cosmic gamma-rays and high-energy protons
  • Supernovae and explosive nucleosynthesis

Selected Publications

  1. Y. Motizuki, Y. Nakai, K. Takahashi, M. Igarashi, H. Motoyama, K. Suzuki:
    "Dating of a Dome Fuji (Antarctica) shallow ice core by volcanic signal synchronization with B32 and EDML1 chronologies",
    The Cryosphere Discussions, 8, 769-804, 2014.
  2. M. Sigl, J.R. McConnell, M. Toohey, M. Curran, S. Das, R. Edwards, E. Isaksson, K. Kawamura, K. Krueger, L. Layman, O. Maselli, Y. Motizuki, D. Pasteris:
    "Rewriting the histroy of volcanic forcing during the Common Era using new ice cores", submitted to Nature Climate Change, 2013.
  3. S. Okamoto, K. Takahashi, Y. Nakai, Y. Motizuki, A. Makabe, K. Koba, H. Motoyama: "Measurement of nitrogen and oxygen isotope ratios in very low nitrate concentration ice core samples",
    submitted to RIKEN Accel. Prog. Rep. 47, 2014.
  4. K. Sekiguchi, Y. Nakai, T. Imamura, H. Akiyoshi, Y. Motizuki:
    "Modeling chemical reactions in the middle atmosphere induced by solar energetic particle events",
    RIKEN Accel. Prog. Rep. 46, 124, 2013.
  5. S. Kikuchi, S. Okamoto, K. Takahashi, Y. Nakai, Y. Motizuki:
    "Annually-resolved water isotope measurements in a shallow ice core drilled in a vicinity of Dome Fuji station, East Antarctica",
    RIKEN Accel. Prog. Rep. 46, 125, 2013.
  6. Y. Motizuki, K. Takahashi, K. Shibata:
    "The occurrence probability of giant solar proton events seeking from ice cores and lunar rocks",
    Bunseki, 10, 585-589, 2012.
  7. R. N. Boyd, M. A. Famiano, B. S. Meyer, Y. Motizuki, T. Kajino, and I. U. Roederer:
    "The r-process in metal-poor stars and black hole formation",
    The Astrophysical Journal Letters, 744, 1, L14-L17, 2012.
  8. M. Igarashi, Y. Nakai, Y. Motizuki, K. Takahashi, H. Motoyama, K. Makishima:
    "Dating of the Dome Fuji shallow ice core based on a record of volcanic eruptions from AD 1260 to AD 2001",
    Polar Science, 5, 411-420, 2011.
  9. Y. Motizuki:
    "Towards opening up the research field of Astro-Glaciology",
    Japan Geoscience Letters, 7, 7-9, 2011.
  10. Y. Motizuki:
    "Footprints of supernovae in our galaxy",
    in:"Ice Cores: Time Capsule for Earth’s Environments", eds. Y. Fujii and H. Motoyama, pp. 185-202, Seizando-Shoten Publishing, Tokyo, Japan, 2011.
  11. Y. Motizuki and K. Sato:
    "The Origin of Elements", in ASJ Current Astronomy Series I,"The Universe and Human Beings", pp. 94-137, eds. S. Okamura et al., Nippon Hyoron Sha Co., Ltd., Tokyo, Japan, 2007.

Lab Members

Principal Investigator

Yuko Motizuki
Group Director

Core Members

Kazuya Takahashi
Senior Research Scientist
Yoichi Nakai
Senior Research Scientist