High precision isotope analyses of presolar grains for the study of stellar nucleosynthesis

2010 Fiscal Year Final Research Report

• Project/Area Number: 21740388
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: Geochemistry/Astrochemistry
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: YOKOYAMA Tetsuya Tokyo Institute of Technology, 大学院・理工学研究科, 准教授 (00467028)
• Project Period (FY): 2009 – 2010
• Keywords: 地球外物質化学 / 高精度同位体分析 / 始原的隕石 / プレソーラー粒子

Research Abstract

We have investigated Os isotope compositions in chondritic acid residues enriched in presolar grains. We found that bulk chondrites contain various types of presolar phases that are rich in either s-process-Os or r-process-Os. The r-process-enriched phases could be extracted from chondrites by a relatively mild acid condition, while s-process-enriched phases appeared to be highly acid resistant. We also found that some r-process-enriched phases were selectively destroyed via parent body aqueous alteration.

Research Products

• [Journal Article] Assessment of nebular versus parent body processes on presolar components present in chondrites : Evidence from osmium isotopes. (2011)
  • Author(s): Yokoyama, T., Alexander, C.M.O'D., Walker, R.J.
  • Journal Title: Earth Planet.Sci.Lett. in press
  • Peer Reviewed
• [Journal Article] Geochemical evolution of historical lavas from Askja Volcano, Iceland : Implications for mechanisms and timescales of magmatic differentiation. (2011)
  • Author(s): Kuritani, T., Yokoyama, T., Kitagawa, H., Kobayashi, K., Nakamura, E.
  • Journal Title: Geochim.Cosmochim.Acta 75 Pages: 570-587
  • Peer Reviewed
• [Journal Article] Timescales of magma differentiation from basalt to andesite beneath Hekla Volcano, Iceland : Constraints from U-series disequilibria in lavas from the last quarter-millennium flows. (2011)
  • Author(s): Chekol, T.A., Kobayashi, K., Yokoyama, T., Sakaguchi, C., Nakamura, E.
  • Journal Title: Geochim.Cosmochim.Acta 75 Pages: 256-283
  • Peer Reviewed
• [Journal Article] isotope anomalies in chondrites : Results for acid residues and related leachates. (2010)
  • Author(s): Yokoyama, T., Alexander, C.M.O'D., Walker, R.J.Osmium
  • Journal Title: Earth Planet.Sci.Lett. 291 Pages: 48-59
  • Peer Reviewed
• [Journal Article] Contributors to chromium isotope variation of meteorites. (2010)
  • Author(s): Qin, L., Alexander, C.M.O'D., Carlson, R.W., Horan, M.F., Yokoyama, T.
  • Journal Title: Geochim.Cosmochim Acta 74 Pages: 1122-1145
  • Peer Reviewed
• [Presentation] Evaluation of parent body processes on presolar components in chondrites : Osmium isotopes in acid residues from CM and CR chondrites. (2011)
  • Author(s): Yokoyama, T., Alexander, C.M.O'D., Walker, R.J.
  • Organizer: 42nd Lunar Planet. Sci. Conf.
  • Place of Presentation: The Woodlands, USA
  • Year and Date: 2011-03-12
• [Presentation] コンドライトの耐酸性残渣のOs同位体異常と母天体プロセス (2010)
  • Author(s): 横山哲也, Alexander, C.M.O'D., Walker, R.J.
  • Organizer: 2010年度質量分析学会同位体比部会
  • Place of Presentation: 別府
  • Year and Date: 2010-11-19
• [Presentation] エンスタタイトコンドライトの耐酸性残渣におけるOs同位体異常 (2010)
  • Author(s): 横山哲也, Alexander, C.M.O'D., Walker, R.J.
  • Organizer: 日本地球惑星連合2010年大会
  • Place of Presentation: 幕張メッセ
  • Year and Date: 2010-05-27
• [Presentation] isotope anomalies in acid residues from enstatite chondrites. (2010)
  • Author(s): Yokoyama, T., Alexander, C.M.O'D., Walker, R.J.
  • Organizer: 41st Lunar Planet. Sci. Conf.
  • Place of Presentation: The Woodlands, USA
  • Year and Date: 2010-03-01
• [Presentation] 始原的隕石の耐酸性残渣におけるOs同位体異常 (2009)
  • Author(s): 横山哲也, Alexander, C.M.O'D., Walker, R.J.
  • Organizer: 2009年度日本地球化学会年会
  • Place of Presentation: 広島大学
  • Year and Date: 2009-09-15
• [Remarks] ホームページ等
  • URL: http://www.geo.titech.ac.jp/lab/yokoyama/