宇宙物質科学・宇宙雪氷学グループ
English

 

Yasuhiro OBA

Career

 

2007 Ph.D at Okayama University
"Stable carbon and hydrogen isotopic compositions of organic matter in carbonaceous meteorites and its implication to alteration processes"

2007.4-2008.3 
Post-doctral scholar at University of Nevada-Reno (USA)
"Oxygen isotope fractionation of dissolved O2 by abiotic reduction"

2008.4-2009.3 
Post-doctral researcher at Institute of Low Temperature Science, Hokkaido Univerisity (JAPAN)
"Laboratory studies on the chemical evolution of interstellar molecules on a low-temperature solid surface"

2009.4-2012.3 
JSPS Post-doctral Fellow (PD) at Institute of Low Temperature Science, Hokkaido University
"Formation of amino acids by atomic surface reactions on interstellar grains at low temperatures"

2012.4-2015.3 
Specially-appointed assistant professor at Institute of Low Temperature Science, Hokkaido University
"Laboratory studies on chemical evolution in molecular clouds"

2015.4-2020.11
Assistant professor at Institute of Low Temperature Science, Hokkaido University
"Laboratory studies on chemical evolution from molecular clouds to planetary systems"

2020.12-present
Associate professor at Institute of Low Temperature Science, Hokkaido University
"Laboratory studies on chemical evolution from molecular clouds to planetary systems and beyond"

Publications

    Refereed Journals

    2021

  1. "Experimental and computational studies on the physico-chemical behavior of phosphine induced by reactions with H and D atoms on interstellar grains."
    T. Nguyen, Y. Oba, W. M. C. Sameera, A. Kouchi, N. Watanabe.
    Astrophysical Journal, in press (2021)

  2. "Transmission electron microscopy study of the morphology of ices composed of H2O, CO2, and CO on refractory grains."
    A. Kouchi, T, Tsuge, T. Hama, Y. Oba, S. Okuzumi, S.-i. Sirono, M. Momose, N. Nakatani, K. Furuya, T. Shimonishi, T. Yamazaki, H. Hidaka, Y. Kimura, K.-i. Murata, K. Fujita, S. Nakatsubo, S. Tachibana, N. Watanabe.
    Astrophysical Journal, in press (2021)

  3. "Formation of chiral CO polyhedral crystals on icy interstellar grains."
    A. Kouchi, M. Tsuge, T. Hama, H. Niinomi, N. Nakatani, T. Shimonishi, Y. Oba, Y. Kimura, S.-i. Sirono, S. Okuzumi, M. Momose, K. Furuya, N. Watanabe.
    Monthly Notices of the Royal Astronomical Society, 505, 1530-1542 (2021)

  4. "Analytical development of seamless procedures on cation-exchange chromatography and ion-pair chromatography with high-precision mass spectrometry for short-chain peptides"
    Y. Takano, Y. Oba, S. Furota, H. Naraoka, N. Ogawa, T. M. Blattmann, N. Ohkouchi
    International Journal of Mass Spectrometry, 463, 116529 (2021)

  5. "FAUST II. Discovery of a secondary outflow in IRAS 15398-3359: Variability in outflow direction during the earliest stage of star formation?"
    Y. Okoda, Y. Oya, L. Francis, D. Johnstone, S. Inutsuka, C. Ceccarelli, C. Codella, C. Chandler, N. Sakai, Y. Aikawa, F. Alves, N. Balucani, E. Bianchi, M. Bouvier, P. Caselli, E. Caux, S. Charnley, S. Choudhury,M. de Simone, F. Dulieu, A. Duran, L. Evans, C. Favre, D. Fedele, S. Feng, F. Fontani, T. Hama, T. Hanawa, E. Herbst, T. Hirota, M. Imai, A. Isella, I. Jimenez-Serra, C. Kahane, B. Lefloch, L. Loinard, A. Lopez-Sepulcre, L. T. Maud, M. J. Maureira, F. Menard, S. Mercimek, A. Miotello, G. Moellenbrock, S. Mori, N. M. Murillo, R. Nakatani, H. Nomura, Y. Oba, R. O'Donoghue, S. Ohashi, J. Ospina-Zamudio, J. Pineda, L. Podio, A. Rimola, T. Sakai, D. S. Cox, Y. Shirley, B. Svoboda, V. Taquet, L. Testi, C. Vastel, S. Viti, N. Watanabe, Y. Watanabe, A. Witzel, C. Xue, Y. Zhang, B. Zhao, S. Yamamoto
    Astrophysical Journal, 910, 11(13pp) (2021)

    2020

  6. "Extraterrestrial hexamethylenetetramine in meteorites-a precursor of prebiotic chemistry in the inner solar system"
    Y. Oba, Y. Takano, H. Naraoka, Y. Furukawa, D. P. Glavin, J. P. Dworkin, S. Tachibana
    Nature Communications, 11, 6243 (2020)
    Press release "Key building block for organic melecules discovered in meteorites", Hokkaido University

  7. *This article is highlighted in "Physics.Org" and many others


  8. "Precometary organic matter: A hidden reservoir of water inside the snow line"
    H. Nakano, N. Hirakawa, Y. Matsubara, S. Yamashita, T. Okuchi, K. Asahina, R. Tanaka, N. Suzuki, H. Naraoka, Y. Takano, S. Tachibana, T. Hama, Y. Oba, Y. Kimura, N. Watanabe, & A. Kouchi
    Scientific Reports, 10, 7755 (2020)


  9. "FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5"
    E. Bianchi, C. Chandler, C. Ceccarelli, C. Codella, N. Sakai, A. Lopez-Sepulcre, L. T. Maud, G. Moellenbrock, B. Svoboda, Y. Watanabe, T. Sakai, F. Menard, Y. Aikawa, F. Alves, N. Balucani, M. de Simone, F. Dulieu, A. Duran, L. Evans, C. Favre, D. Fedele, S. Feng, F. Fontani, L. Francis, T. Hama, T. Hanawa, E. Herbst, T. Hirota, M. Imai, A. Isella, I. Jimenez-Serra, D. Johnstone, C. Kahane, B. Lefloch, N. M. Murillo, R. Nakatani, H. Nomura, Y. Oba, S. Ohashi, Y. Okoda, J. Ospina-Zamudio, Y. Oya, J. Pineda, L. Podio, A. Rimola, D. S. Cox, Y. Shirley, V. Taquet, L. Testi, C. Vastel, S. Viti, N. Watanabe, A. Witzel, C. Xue, Y. Zhang, B. Zhao, & S. Yamamoto
    Monthly Notices of the Royal Astronomical Society Letters, 498, L87-L92 (2020).


  10. "UV-ray irradiation never causes amorphization of crystalline CO2: A transmission electron microscopy study"
    M. Tsuge, T. Nguyen, Y. Oba, T. Hama, A. Kouchi, and N. Watanabe
    Chemical Physics Letters, 760, 137999 (2020)


  11. "An experimental study of chemica ldesorption for phosphine in interstellar ice"
    T. Nguyen, Y. Oba, A. Kouchi, and N. Watanabe
    Astrophysical Journal Letters, 898, L52 (6pp) (2020)

    2019

  12. "Nucleobase synthesis in interstellar ices"
    Oba Y.,Takano Y., Naraoka H., Watanabe N. and Kouchi A.
    Nature Communications, 10, 4413 (2019)
    Press release "Life's building blocks may have formed in interstellar clouds", Hokkaido University

  13. *This article is highlighted in "Fox News" and many others


  14. "Physico-chemical behabior of hydrogen sulfide induced by reactions with H and D atoms on different types of ice surfaces at low temperature"
    Oba Y.,Tomaru T., Kouchi A. and Watanabe N.
    Astrophysical Journal, 874,124 (8pp) (2019)

    2018

  15. "An infrared measurement of chemical desorption from interstellar ice analogues"
    Oba Y.,Tomaru T., Lamberts T., Kouchi A. and Watanabe N.
    Nature Astronomy, 2, 228-232 (2018) doi:10.1038/s41550-018-0380-9
    Press release "Baby, it’s cold outside: understanding conditions for star formation", Hokkaido University

    2017

  16. "Deuterium fractionation upon the formation of hexamethylenetetramines through photochemical reactions of interstellar ice analogs containing deuterated methanol isotopologues"
    Oba Y.,Takano Y., Naraoka H., Kouchi A. and Watanabe N.
    Astrophysical Journal, 849, 122 (9pp) (2017)


  17. "Liquid-like behavior of UV-irradiated interstellar ice analog at low temperatures"
    Tachibana S., Kouchi A., Hama T., Oba Y., Piani L., Sugawara I., Endo Y., Hidaka H., Kimura Y., Murata K., Yurimoto H, and Watanabe N.
    Science Advances, 3, eaao2538 (2017)


  18. 2016

  19. "Negative catalytic effect of water on the reactivity of hydrogen abstraction from the C-H bond of dimethyl ether by deuterium atoms through tunneling at low temperatures"
    Oba Y., Watanabe N., and Kouchi A.
    Chemical Physics Letters, 662, 14-18 (2016)
    *This article is selected as "Editors Choice".


  20. "Hydrogen-deuterium substitution in solid ethanol by surface reactions at low temperatures"
    Oba Y., Osaka K., Chigai T., Kouchi A., and Watanabe N.
    Monthly Notices of Royal Astronomical Society, 462, 689-695 (2016)


  21. "Deuterium fractionation during amino acid formation by photolysis of interstellar ice analogues containing deuterated methanol"
    Oba Y.,Takano Y., Watanabe N., and Kouchi A.
    Astrophysical Journal Letters, 827, L18 (7pp) (2016)


  22. 2015

  23. "Chiral Glycine Formation on Cold Interstellar Grains by Quantum Tunneling Hydrogen-Deuterium Substitution Reactions"
    Oba Y., Watanabe N., Osamura Y., and Kouchi A.
    Chemical Physics Letters, 634, 53-59 (2015)
    *This article is selected as "Editors Choice".
    *This article is highlighted in "The Conversation"
    *This article is highlighted in "Cosmos Magagine"
    Press release "Formation Route of First Chiral Amino Acid in the Universe Clarified", Hokkaido University


  24. 2014

  25. "Hydrogen Isotopic Substitution of Solid Methylamine through Atomic Surface Reactions at Low Temperatures: A Potential Contribution to the D/H Ratio of Methylamine in Molecular Clouds"
    Oba Y., Chigai T., Osamura Y., Watanabe N., and Kouchi A.
    Meteoritics & Planetary Science, 49, 117-132 (2014)


  26. "Reaction kinetics and isotope effect of water formation by the surface reaction of solid H2O2 with H atoms at low temperatures"
    Oba Y., Osaka K., Watanabe N., Chigai T., and Kouchi A.
    Faraday Discussions, 168, 185-204 (2014)


  27. 2012

  28. "Physicochemical Processes of Hydrogen on Cosmic Dust in Molecular Clouds"
    Naoki WATANABE, Akira KOUCHI, Tetsuya HAMA, Hiroshi HIDAKA, Yasuhiro OBA, Takeshi CHIGAI
    Hyomen Kagaku (in Japanese), 33, 662-668 (2012)


  29. "Octanol-water partition coefficients (Kow) vs. pH for fluorescent dye tracers (fluorescein, eosin Y), and implications for hydrologic tracer tests."
    Oba Y., and Poulson S. R.
    Geochemical Journal, 46, 517-520 (2012)


  30. "Water formation through a quantum tunneling surface reaction, OH + H2, at 10 K."
    Oba Y., Watanabe N., Hama T., Kuwahata K., Hidaka H., and Kouchi A.
    The Astrophysical Journal, 749, 67(12pp) (2012)


  31. 2011

  32. "Experimental studies of surface reactions among OH radicals that yield H2O and CO2 at 40-60 K."
    Oba Y., Watanabe N., Kouchi A., Hama T., and Pirronello V.
    Physical Chemistry Chemical Physics, 13, 15792-15797 (2011)


  33. "Experimental studies on the formation of carbon dioxide in interstellar molecular clouds"
    Yasuhiro OBA, Naoki WATANABE, Akira KOUCHI, Tetsuya HAMA, Valerio PIRRONELLO
    Chikyu Kagaku (in Japanese), 45, 213-226 (2011)


  34. "Stable isotopic composition of organic compouds in carbonaceous chondrites and their fractionation processes"
    Yasuhiro OBA
    Researches in Organic Geochemistry (in Japanese), 27, 103-115 (2011)


  35. 2010

  36. "Formation of carbonic acid (H2CO3) by surface reactions of non-energetic OH radicals with CO molecules at low temperatures"
    Oba Y., Watanabe N., Kouchi A., Hama T., and Pirronello V.
    The Astrophysical Journal, 722, 1598-1606 (2010)


  37. "Vertical carbon isotope change in acetate in a surface sediment from the northwestern Pacific Ocean"
    Kaneko, M., Oba Y., and Naraoka, H.
    Researches in Organic Geochemistry, 26, 73-79 (2010)


  38. "Direct evidence for ammonium ion formation in ice through ultraviolet-induced acid-base reaction of NH3 with H3O+"
    Moon E.-S., Kang H., Oba Y., Watanabe N., and Kouchi A.
    The Astrophysical Journal, 713, 906-911 (2010)


  39. "Experimental study of CO2 formation by surface reactions of non-energetic OH radicals with CO molecules"
    Oba Y., Watanabe N., Kouchi A., Hama T., and Pirronello V.
    The Astrophysical Journal, 712, L174-L178 (2010)


  40. "Diel behavior of stable isotopes of dissolved oxygen and dissolved inorganic carbon in rivers over a range of trophic conditions, and in a mesocosm experiment."
    S. R. Parker, C. H. Gammons, S. R. Poulson, M. D. DeGrandpre, C. L. Weyer, M. G. Smith, J. N. Babcock, and Oba Y.
    Chemical Geology, 269, 22-32 (2010)


  41. 2009

  42. "Oxygen isotope fractionation of dissolved oxygen during abiological reduction by aqueous sulfide"
    Oba Y., and Poulson S.R.
    Chemical Geology, 268, 226-232 (2009)


  43. "Elemental and isotope behavior of macromolecular organic matter from CM chondrites during hydrous pyrolysis"
    Oba Y., and Naraoka H.
    Meteoritics and Planetary Science, 44, 943-953 (2009)


  44. "Formation of compact amorphous H2O ice by codeposition of hydrogen atoms with oxygen molecules on grain surfaces"
    Oba Y., Miyauchi N., Chigai T., Hidaka H., Watanabe N., and Kouchi A.
    The Astrophysical Journal, 701, 464-470 (2009)


  45. "Oxygen isotope fractionation of dissolved oxygen during reduction by ferrous iron"
    Oba Y., and Poulson S.R.
    Geochimica et Cosmochimica Acta, 73, 13-24 (2009)


  46. "Formation of water molecule by surface atomic reactions on interstellar grains at low temperatures"
    Yasuhiro OBA,Naoya MIYAUCHI,Takeshi CHIGAI,Hiroshi HIDAKA,Naoki WATANABE,Akira KOUCHI
    Chikyu Kagaku (in Japanese), 43, 117-131 (2009)


  47. 2008

  48. "Carbon and hydrogen isotopic fractionation of low molecular weight organic compounds during ultraviolet degradation"
    Oba Y., and Naraoka H.
    Organic Geochemistry, 35, 501-509 (2008)


  49. "Compound-specific isotope analysis (CSIA) by gas chromatograph/isotope ratio mass spectrometer (GC/IRMS)"
    Yoshito CHIKARAISHI,Yasuhiro OBA
    Researches in Organic Geochemistry (in Japanese), 23/24, 99-122 (2008)


  50. 2007

  51. "Carbon and hydrogen isotope fractionation of acetic acid during degradation by ultraviolet light"
    Oba Y., and Naraoka H.
    Geochemical Journal, 41, 103-110 (2007)


  52. 2006

  53. "Site-specific carbon isotope analysis of aromatic carboxylic acids by elemental analysis-pyrolysis-isotope ratio mass spectrometry"
    Oba Y., and Naraoka H.
    Rapid Communications in Mass Spectrometry, 20, 3649-3653 (2006)


  54. "Carbon isotopic composition of acetic acid generated by hydrous pyrolysis of macromolecular organic matter from the Murchison meteorite"
    Oba Y., and Naraoka H.
    Meteoritics and Planetary Science, 41, 1175-1181 (2006)


  55. 2003

  56. " Different behavior of hydrogen isotope exchange in aqueous solutions between two PAH isomers (fluoranthene and pyrene)"
    Oba Y., and Naraoka H.
    Researches in Organic Geochemistry, 18, 29-35 (2003)

Conference Proceedings


  1. V. Pirronello, M. Accolla, T. Hama, H. Hidaka, A. Kouchi, G. Manico,
    Y. Oba, and N. Watanabe
    "Laboratory investigations of physico-chemical processes occurring in icy mantles on interstellar dust grains"
    Physics and Chemistry of ice 2010, pp 361-368, Hokkaido University press (2011)


  2. Y. Oba, N. Miyauchi, T. Chigai, H. Hidaka, N. Watanabe, and A. Kouchi
    "Formation of H2O ice through the surface reaction O2 + H at low temperatures: Reaction kinetics and structure of the ice"
    Physics and Chemistry of ice 2010, pp 369-378, Hokkaido University press (2011)


  3. A. Kouchi, N. Watanabe, H. Hidaka, N. Miyauchi, Oba Y., and T. Chigai,
    "Formation of amorphous H2O ice from the reactions of cold H atoms with solid O2 at 10K"
    Cosmic Dust-Near & Far, ASP Conference Series 414, 338, (2009)


  4. N. Watanabe, A. Kouchi, H. Hidaka, Oba Y., and N. Miyauchi,
    "Nonenergetic reactions between atomic hydrogen and molecules on interstellar grain surfaces"
    XXVI International Conference on Photonic, Electronic and Atomic Collisions,
    Journal of Physics: Conference Series,
    194, 012044, (2009)

Invited talks


    "Recent advances in analytical techniques for the identification of specific COMs in photochemically-processed interstellar ice analogs"
    43rd COSPAR Scientific Assembly, F3.5,Sydney (online), 31st Jan.(2021)
    "H2S, why you no solid at 10 K? -Nonthermal desorption from interstellar icy grains"
    JPGU 2018 Meeting, Chiba, Japan, 22nd May (2018)
    "Experimental studies on the surface reaction of hydrogen sulfide with deuterium atoms on amorphous solid water at 10 K"
    ACS Spring National Meeting, New Orleans, USA, 21st March (2018)
    "Formation of chiral glycine by surface reactions of normal glycine with deuterium atoms at 10 K"
    Astrophysical Ices in the Lab (AILab),
    Madrid, Spain, 7-8th March (2016)
    "Formation and deuterium fractionation of water by low-temperature surface reactions in molecular clouds"
    Center for Astrochemical Studies Seminar, Munich, Germany, 13th October (2015)
    "Formation of H2O ice on cold interstellar grains: Reaction kinetics and the structure of ice"
    Workshop on Ice and Water Films,Seoul, Korea, 6-8 May (2013)
    "Co-evolution of water and organics via surface reactions on interstellar grains"
    JPGU 2013 Meeting,Chiba, Japan, 22 May (2013)
    "Structure of H2O ice formed by surface reactions of oxygen molecules with hydrogen atoms at low temperatures",
    12th International Conference on the Physics and Chemistry of Ice, Hokkaido Univ., 5-10 September, (2010)
    "Formation of compact amorphous water ice by surface atomic reactions at low temperatures",
    2010 Western Pacific Geophysics Meeting, Taipei, Taiwan, 22-25 June, (2010)

Award


  • Young investigator award from The Japanese Association of Organic Geochemists (2010) "Stable isotope compositions of organic compounds in carbonaceous chondrites and its isotope fractionation processes"


  • The Geochemistry Research Association Award for Progress in Geochemistry (2017) "Studies on organic molecules in carbonaceous chondrites and on molecules under simulated interstellar conditions using their stable isotope compositions by novel experimental methods"