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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. Yichen Zhang, Jonathan C. Tan, Nami Sakai, Kei E. I. Tanaka, James M. De Buizer, Mengyao Liu, Maria T. Beltran, Kaitlin Kratter, Diego Mardones, and Guido Garay.:
    "An Ordered Envelope-Disk Transition in the Massive Protostellar Source G339.88-1.26"
    ApJ, 873, 73, 29pp (2019)
  • 2. Nami Sakai, Tomoyuki Hanawa, Yichen Zhang, Aya E. Higuchi, Satoshi Ohashi, Yoko Oya, and Satoshi Yamamoto.:
    "A warped disk around an infant protostar"
    Nature, 565, p206-208 (2019)
  • 3. Yuji Ebisawa, Nami Sakai, Karl M. Menten, and Satoshi Yamamoto.:
    "The Effect of Far-infrared Radiation on the Hyperfine Anomaly of the OH 18cm Transition"
    ApJ, 871, 89, 28pp (2019)
  • 4. Aya E. Higuchi, Nami Sakai, Yoshimasa Watanabe, Ana Lopez-Sepulcre, Kento Yoshida, Yoko Oya, Muneaki Imai, Yichen Zhang, Cecilia Ceccarelli, Bertrand Lefloch, Claudio Codella, Rafael Bachiller, Tomoya Hirota, Takeshi Sakai, and Satoshi Yamamoto.:
    "Chemical Survey toward Young Stellar Objects in the Perseus Molecular Cloud Complex"
    ApJ, Suppl. Ser., 236, 52, 25pp (2018)
  • 5. Satoshi Ohashi, Patricio Sanhueza, Nami Sakai, Ryo Kandori, Minho Choi, Tomoya Hirota, Quang Nguyn-Lu'o'ng, and Ken'ichi Tatematsu.:
    "Gravitationally Unstable Condensations Revealed by ALMA in the TUKH122 Prestellar Core in the Orion A Cloud"
    ApJ, 856, 147, 12pp (2018)
  • 6. Tatsuya Soma, Nami Sakai, Yoshimasa Watanabe, and Satoshi Yamamoto.:
    "Complex Organic Molecules in Taurus Molecular Cloud-1"
    ApJ, 854, 116, 11pp (2018)
  • 7. 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, Lett., 839, L14, 6pp (2017)
  • 8. 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)
  • 9. *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, p78-80 (2014)
  • 10. *Nami Sakai and Satoshi Yamamoto.:
    "Warm Carbon-Chain Chemistry"
    Chem. Rev., 113, p8981-9015 (2013)

Recent Research Results

Annual research report

Related Links

Lab Members

Principal investigator

Nami Sakai
Chief Scientist

Core members

Satoshi Ohashi
Research Scientist
Yichen Zhang
Special Postdoctoral Researcher
Hideki Umehata
Special Postdoctoral Researcher
Ryohei Nakatani
Special Postdoctoral Researcher
Shota Notsu
Special Postdoctoral Researcher
Akemi Tamanai
Contract Researcher
Ziwei Zhang
Postdoctoral Researcher
Nadia Mariel Murillo Mejias
Postdoctoral Researcher
Shaoshan Zeng
Postdoctoral Researcher
Yuki Ohno
Student Trainee

Contact Information

S407 Chemistry and Materials Physics Building,
2-1 Hirosawa,
Wako, Saitama
351-0198, Japan
Email: nami.sakai [at] riken.jp