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Chief Scientist Laboratories Star and Planet Formation Laboratory

Chief Scientist: Nami Sakai (Ph.D.)

Research Summary

Nami  Sakai(Ph.D.)

Star and planet formation is one of the most fundamental structure-formation processes in the universe. By use of the state-of-the-art radio telescopes including ALMA, we are investigating when a disk structure is formed around a solar-type protostar, and how it is evolved into a protoplanetary disk and eventually to a planetary system. This is an essential question deeply related to the origin of the Solar system. We particularly focus on a relation between physical evolution and chemical evolution during star and planet formation. Related laboratory spectroscopic studies in the millimeter and submillimeter regimes are also planned.

Main Research Fields

  • Mathematical & Physical Sciences

Related Research Fields

  • Interdisciplinary Science & Engineering
  • Chemistry
  • Astronomy
  • Physics
  • Earth and planetary science


  • Star formation
  • Planetary system formation
  • Radio astronomy
  • Astrochemistry
  • Spectroscopy

Selected Publications

Papers with an asterisk(*) are based on research conducted outside of RIKEN.

  • 1.Aya E. Higuchi, Aki Sato, Takashi Tsukagoshi, Nami Sakai, Kazunari Iwasaki, Munetake Momose, Hiroshi Kobayashi, Daisuke Ishihara, Sakae Watanabe, Hidehiro Kaneda, and Satoshi Yamamoto.:
    "Detection of Submillimeter-wave [CI] Emission in Gaseous Debris Disks of 49 Ceti and βPictoris"
    ApJ, 839:L14 (2017)
  • 2.Nami Sakai, Yoko Oya, Aya E. Higuchi, Yuri Aikawa, Tomoyuki Hanawa, Cecilia Ceccarelli, Bertrand Lefloch, Ana Lopez-Sepulcre, Yoshimasa Watanabe, Takeshi Sakai, Tomoya Hirota, Emmanuel Caux, Charlotte Vastel, Claudine Kahane, and Satoshi Yamamoto.:
    "Vertical structure of the transition zone from infalling rotating envelope to disc in the Class 0 protostar, IRAS 04368+2557"
    MNRAS 467, L76-L80 (2017)
  • 3.Yoko Oya, Nami Sakai, Ana Lopez-Sepulcre, Yoshimasa Watanabe, Cecilia Ceccarelli, Bertrand Lefloch, Cecile Favre, and Satoshi Yamamoto.:
    "Infalling-rotating motion and associated chemical change in the envelope of IRAS 16293-2422 source a studied with ALMA"
    ApJ 824-88 (2016)
  • 4.Yuji Ebisawa, Hiroshi Inokuma, Nami Sakai, Karl M. Menten, Hiroyuki Maezawa, and Satoshi Yamamoto.:
    "OH 18 cm Transition as a Thermometer for Molecular Clouds"
    ApJ, 815, 13 (2015)
  • 5.Kento Yoshida, Nami Sakai, Tomoya Tokudome, Ana López-Sepulcre, Yoshimasa Watanabe, Shuro Takano, Bertrand Lefloch, Cecilia Ceccarelli, Rafael Bachiller, Emmanuel Caux, Charlotte Vastel, and Satoshi Yamamoto.:
    "Abundance Anomaly of the13C Isotopic Species of c-C3H2 in the Low-Mass Star Formation Region L1527"
    ApJ, 807, 66 (2015)
  • 6.*Nami Sakai, Takeshi Sakai, Tomoya Hirota, Yoshimasa Watanabe, Cecilia Ceccarelli, Claudine Kahane, Sandrine Bottinelli, Emmanuel Caux, Karine Demyk, charlotte Vastel, Audrey Cautens, Vianney Taquet, Nagayoshi Ohashi, Shigehisa Takakuwa, His-Wei Yen, Yuri Aikawa, and Satoshi Yamamoto.:
    "Change in the chemical composition of infalling gas forming a disk around a protostar"
    Nature, 507, 78 (2014)
  • 7.*Nami Sakai and Satoshi Yamamoto.:
    "Warm Carbon-Chain Chemistry"
    Chem. Rev., 113, 8981 (2013)
  • 8.*Nami Sakai, Shuro Takano, Takeshi Sakai, Shoichi Shiba, Yoshihiro Sumiyoshi, Yasuki Endo, and Satoshi Yamamoto.:
    "Anomalous13C Isotope Abundances in C3S and C4H Observed toward the Cold Interstellar Cloud, Taurus Molecular Cloud-1"
    J. Phys. Chem., 117, 9831 (2013)
  • 9.*Nami Sakai, Hiroyuki Maezawa, Takeshi Sakai, Karl M. Menten, and Satoshi Yamamoto.:
    "CH radio emission from Heiles Cloud 2 as a tracer of molecular cloud evolution"
    Astron. Astrophys., 546, A103 (2012)
  • 10.*Nami Sakai, Takeshi Sakai, Yoshihiro Osamura, and Satoshi Yamamoto.:
    "Detection of C6H¯ toward the low-mass protostar IRAS 04368+2557 in L1527"
    ApJ 667: L65-L68 (2007)

Recent Research Results

Annual research report

Related Links

Lab Members

Principal investigator

Nami Sakai
Chief Scientist

Core members

Satoshi Ohashi
Special Postdoctoral Researcher
Yichen Zhang
Special Postdoctoral Researcher
Hideki Umehata
Special Postdoctoral Researcher
Ryohei Nakatani
Special Postdoctoral Researcher
Akemi Tamanai
Contract Researcher
Yao-Lun Yang
Visiting Researcher
Yoshimasa Watanabe
Visiting Scientist

Contact Information

S407 Chemistry and Materials Physics Building,
2-1 Hirosawa,
Wako, Saitama
351-0198, Japan

Email: nami.sakai [at] riken.jp