Centers & Labs

Associate Chief Scientist Laboratories

Star and Planet Formation Laboratory

Associate Chief Scientist: Nami Sakai (Ph.D.)
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 Field


Related Research Fields

Chemistry / Multidisciplinary / Space Science / Geosciences

Research Subjects

  • Formation of protostar and protoplanetary disks
  • Tracing chemical processes in interstellar clouds
  • Millimeter- and submillimeter-wave spectroscopy for molecules of astrochemical interests

Selected Publications

Papers with an asterisk(*) are based on research conducted outside of RIKEN.
  1. 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).
  2. 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 the 13C Isotopic Species of c-C3H2 in the Low-Mass Star Formation Region L1527"
    ApJ, 807, 66 (2015).
  3. *Nami Sakai, Yoko, Oya, Takeshi Sakai, Yoshimasa Watanabe, Tomoya Hirota, Cecilia Ceccarelli, Claudine Kahane, Ana Lopez-Sepulcre, Bertrand Lefloch, Charlotte Vastel, Sandrine Bottinelli, Emmanuel Caux, Audrey Cautens, Yuri Aikawa, Shigehisa Takakuwa, Nagayoshi Ohashi, His-Wei Yen, and Satoshi Yamamoto:
    "A chemical view of protostellar-disk formation in L1527"
    ApJ, 791, L38 (2014).
  4. *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).
  5. *Nami Sakai and Satoshi Yamamoto:
    "Warm Carbon-Chain Chemistry"
    Chem. Rev., 113, 8981 (2013).
  6. *Nami Sakai, Shuro Takano, Takeshi Sakai, Shoichi Shiba, Yoshihiro Sumiyoshi, Yasuki Endo, and Satoshi Yamamoto:
    "Anomalous 13C Isotope Abundances in C3S and C4H Observed toward the Cold Interstellar Cloud, Taurus Molecular Cloud-1"
    J. Phys. Chem., 117, 9831 (2013)
  7. *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)
  8. *Nami Sakai, Tatsuya Shiino, Tomoya Hirota, Takeshi Sakai, and Satoshi Yamamoto:
    "Long carbon-chain molecules and their anions in the starless core, Lupus-1A"
    Astrophys. J., 718, L49 (2010)
  9. *Nami Sakai, Osamu Saruwatari, Takeshi Sakai, Shuro Takano, and Satoshi Yamamoto:
    "Abundance anomaly of the 13C species of CCH"
    Astron. Astrophys., 512, A31 (2010)
  10. *Nami Sakai, Takeshi Sakai, Tomoya Hirota, and Satoshi Yamamoto:
    "Deuterated molecules in warm carbon chain chemistry: The L1527 case"
    Astrophys. J., 702, 1025 (2009)

Lab Members

Principal Investigator

Nami Sakai
Associate Chief Scientist

Core Members

Yichen Zhang
Postdoctoral Researcher
Aya Higuchi
Contract Researcher
Kento Yoshida
Junior Research Associate
Yutaro Chiba
Student Trainee
Ritsuko Matsumoto
Part-time Worker

Contact information

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

Email: nami.sakai [at]

Related links

Recent research results

February 10, 2017: Press Release
Protostar displays a strange geometry

Annual research report