Chushiro Hayashi

Chushiro Hayashi


Date of Birth
July 25, 1920
Date of Death
February 28, 2010

Born in Kyoto, Chushiro Hayashi earned his B.S. in physics at the University of Tokyo in 1942. After World War II he served as a research associate under Hideki Yukawa at Kyoto University, and as an associate professor of physics at Naniwa (now Osaka Prefecture) University. He was at Kyoto University, where he earned his doctorate, from 1954 until his retirement in 1984. In 1950 he made a significant contribution to the αβγ (Alpher-Bethe-Gamow) model of nucleosynthesis in the hot big bang. Hayashi showed that at the high temperatures characteristic of the very early universe, electron-positron pair production had to be taken into account, and this led to revisions in the estimate of the early neutron-proton ratio and a better value for the ultimate abundance of helium in the universe. Hayashi was one of the pioneers in modeling stellar evolution in the 1950s and ’60s. He is best known for his models of star formation and pre-main sequence evolution. Demonstrating that they are fully convective and not in hydrostatic equilibrium, he found that pre-main-sequence stars follow what are now called “Hayashi tracks” downward on the Hertzprung-Russell diagram until they reach the main sequence, i.e., they contract at near-constant surface temperature. Hayashi also worked on the formation of low-mass stars—he and Takenori Nakano made one of the earliest studies of what are now called brown dwarfs—and he investigated the formation of the solar system and of the earth and its atmosphere. He was a leader in building astrophysics in Japan, and some of today’s foremost theorists are his former students. Note: He was also known as Hayashi Chushiro.

Presentation of Bruce medal

Mercury 34, 4, 43 (Jul/Aug 2004).

Other awards

Inamori Foundation, Kyoto Prize for Basic Science, 1995.
Royal Astronomical Society, Eddington medal, 1970, presented by Bernard Lovell, QJRAS 11, 88 (1970).

Biographical materials

Bitterman, Jay, Lake County Astronomical Society
Hayashi, Chushiro, curriculum vitae, 1991.


Nakagawa, Yoshitsugu, Bull. Am. Astron. Soc. 43, 14 (2011).
Sugimoto, Daiichiro, Astronomy & Geophysics 51, 3.36 (2010).

Academic genealogy


Named after him

Minor Planet #12141 Chushayashi
Hayashi Tracks
Hayashi Chushiro Prize of the Astronomical Society of Japan


Other References: Historical

Nakano, Takenori, “Research on the Bottom of the Main Sequence and Brown Dwarfs in the Early Days,” in Eduardo Martín, ed., Brown Dwarfs, Proceedings of IAU Symposium #211, held 20-24 May 2002 at University of Hawaii, Honolulu, Hawaii (Astronomical Society of the Pacific, San Francisco, 2003), p. 551-52.

Nakano, T., “Professor C. Hayashi and the Research on Star Formation,” Astronomical Herald 80, 164-67 (1987).

Sato, H., “Simple theory of stellar structure. Research with Professor Hayashi,” Astronomical Herald 80, 256-60 (1987).

Stahler, Steven W., “Understanding Young Stars: A History,” PASP 100, 1474 (1988).

Sugimoto, D., “When Hayashi Phase was Discovered,” Astronomical Herald 89, 116-23 (1996) [abstract].

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Other References: Scientific

Hayashi, Chushiro, “Giant Stars Producing Energy by C-N Reactions,” Prog. Theoret. Phys. 2, 127-34 (1947).

Hayashi, Chushiro, “Stars Built on the Shell Source Model,” Phys. Rev. 75, 1619 (1949).

Hayashi, Chushiro, “Proton-Neutron Concentration Ratio in the Expanding Universe at the Stages Preceding the Formation of the Elements,” Prog. Theoret. Phys. 5, 224-35 (1950).

Hayashi, Chushiro, “On Field Equations with Non-Local Interaction,” Prog. Theoret. Phys. 11, 226-27 (1954).

Hayakawa, Satio, Chushiro Hayashi, Mitsuo Imoto, & Ken Kikuchi, ”Helium Capturing Reactions in Stars,” Prog. Theoret. Phys. 16, 507-27 (1956) [errata].

Hayashi, Chushiro & Minoru Nishida, “Formation of Light Nuclei in the Expanding Universe,” Prog. Theoret. Phys. 16, 613-24 (1956).

Hayashi, Chushiro, Tadao Nakano, Minoru Nishida, Shota Suekane, & Yoshio Yamaguchi, “The Catalysis of Nuclear Fusion Reactions by μ Mesons,” Prog. Theoret. Phys. 17, 615-16 (1957).

Hayashi, Chushiro, “Giant Stars with Shell Sources of C-N and p-p Reactions,” Prog. Theoret. Phys. 17, 737-42 (1957).

Sakashita, Shiro, Yoro Ono, & Chushiro Hayashi, “The Evolution of Massive Stars. I.” Prog. Theoret. Phys. 21, 315-23 (1959).

Hayashi, Chushiro, Minoru Nishida, Noboru Ohyama & Hiroshi Tsuda, “Stellar Synthesis of the α-Particle Nuclei Heavier than 20Ne,” Prog. Theoret. Phys. 22, 101-27 (1959).

Hayashi, Chushiro, Jun Jugaku, & Minoru Nishida, “Evolution of Massive Stars. II.” Prog. Theoret. Phys. 22, 531-43 (1959).

Sakashita, Shiro & Chushiro Hayashi,“Internal Structure and Evolution of Very Massive Stars,” Prog. Theoret. Phys. 22, 830-34 (1959).

Hayakawa, S., C. Hayashi, K. Ito, J. Jugaku, M. Nishida, & N. Ohyama, “Chemical Composition of Cosmic Rays and Origin of Elements,” in S.I. Syrovatsky, ed., Proceedings from the 6th International Cosmic Ray Conference, held in Moscow, Russia, 1960. Vol. 3, p.171-80.

Hayashi, C., J. Jugaku, & M. Nishida, “Models of Massive Stars in Helium-Burning Stage,” Ap.J. 131, 241-43 (1960).

Hayakawa, S., C. Hayashi, & M. Nishida, “Rapid Thermonuclear Reactions in Supernova Explosion,” Progr. Theoret. Phys. Supp. 16, 169-97 (1960).

Hayashi, Chushiro & Reun Hoshi, “The Outer Envelope of Giant Stars with Surface Convection Zone,” Publ. Astr. Soc. Japan 13, 442-49 (1961).

Hayashi, Chushiro, Minoru Nishida, & Daiichiro Sugimoto, “Evolution of a Star with Intermediate Mass after Hydrogen Burning” Prog. Theoret. Phys. 25, 1053-56 (1961).

Hayashi, Chushiro, “Stellar Evolution in Early Phases of Gravitational Contraction,” Publ. Astr. Soc. Japan 13, 450-452 (1961) [reprinted, with commentary, in Lang, Kenneth R. & Owen Gingerich, eds., A Source Book in Astronomy & Astrophysics, 1900-1975 (Harvard Univ. Press, 1979), 364-65, 371-73.] .

Hayashi, Chushiro, Minoru Nishida, & Daiichiro Sugimoto, “Evolution of a Star with Intermediate Mass after Hydrogen Burning. I.” Prog. Theoret. Phys. 27, 1233-52 (1962).

Hayashi, Chushiro & Robert C. Cameron, “The Evolution of Massive Stars. III. Hydrogen Exhaustion Through the Onset of Carbon-Burning,” Ap.J. 136, 166-92 (1962).

Hayashi, Chushiro, Reun Hoshi, & Daiichiro Sugimoto, “Evolution of the Stars,” Progr. Theoret. Phys. Supp. 22, 1-183 (1962).

Hayashi, Chushiro & Takenori Nakano, “Evolution of Stars of Small Masses in the Pre-Main Sequence Stages,” Progr. Theoret. Phys. 30, 460-74 (1963).

Komita, Kenji & Chushiro Hayashi, “The Cosmical Constant and the Age of the Universe,” Prog. Theoret. Phys. 30, 691-98 (1963).

Hayashi, Chushiro & Takenori Nakano, “Contraction of a Protostar up to the Stage of Quasi-Static Equilibrium,” Progr. Theoret. Phys. 33, 554-56 (1965).

Hayashi, Chushiro & Takenori Nakano, “Thermal and Dynamical Properties of a Protostar and Its Contraction to the Stage of Quasi-Static Equilibrium,” Progr. Theoret. Phys. 34, 754-75 (1965).

Hayashi, Chushiro, Reiun Hoshi, & Daiichiro Sugimoto, “Advanced Phases of Evolution of Population II Stars: Growth of the Carbon Core and Shell Helium Flashes,” Prog. Theoret. Phys. 34, 885-911 (1965).

Hayashi, Chushiro, “Evolution of Protostars,” Ann. Revs. Astron. Astrophys. 4, 171-92 (1966).

Hayashi, Chushiro, “Advanced Stages of Stellar Evolution,” in R. F. Stein and A.G.W. Cameron, eds., Stellar Evolution, Proceedings of an International Conference, held at the Goddard Space Flight Center, Greenbelt, November 13-15, 1963 (Plenum Press, NY, 1966), p. 253.

Murai, Tadayuki , Daiichiro Sugimoto, Reiun Hoshi, & Chushiro Hayashi, “Evolution of Carbon Stars. I. Gravitational Contraction and Onset of Carbon Burning,” Progr. Theoret. Phys. 39, 619-634 (1968).

Sugimoto, Daiichiro, Yoshiaki Yamamoto, Reiun Hoshi, & Chushiro Hayashi, “Evolution of Carbon Stars. II. Carbon Burning Phase,” Progr. Theoret. Phys. 39, 1432-47 (1968).

Nakano, Takenori, Noboru Ohyama, & Chushiro Hayashi, “Rapid Contraction of a Protostar to the Stage of Quasi-Hydrostatic Equilibrium. I. The Case of One Solar Mass without Radiation Flow,” Progr. Theoret. Phys. 39, 1448-1467 (1968).

Kusaka, Takashi, Takenori Nakano & Chushiro Hayashi, “Growth of Solid Particles in the Primordial Solar Nebula,” Progr. Theoret. Phys. 44, 1580-95 (1970).

Hayashi, Chushiro & Yoshitsugu Nakagawa, “Size Distribution of Grains Growing by Thermal Grain-Grain Collision,” Progr. Theoret. Phys. 54, 93-103 (1975).

Hayashi, Chushiro, Isao Adachi, & Kiyoshi Nakazawa, “Formation of the Planets,” Progr. Theoret. Phys. 55, 945-46 (1976).

Adachi, Isao, Chushiro Hayashi & Kiyoshi Nakazawa, “The Gas Drag Effect on the Elliptic Motion of a Solid Body in the Primordial Solar Nebula,” Progr. Theoret. Phys. 56, 1756-1771 (1976).

Hayashi, Chushiro, Kiyoshi Nakazawa, & Isao Adachi, “Long-Term Behavior of Planetesimals and the Formation of the Planets,” Publ. Astr. Soc. Japan 29, 163-96 (1977).

Takahara, Mariko, Kiyoshi Nakazawa, Shinji Narita, & Chushiro Hayashi, “Adiabatic Collapse of Rotating Gas Clouds,” Progr. Theoret. Phys. 58, 536-48 (1977).

Mizuno, Hiroshi, Kiyoshi Nakazawa, & Chushiro Hayashi, “Instability of a Gaseous Envelope Surrounding a Planetary Core and Formation of Giant Planets,” Progr. Theoret. Phys. 60, 699-710 (1978).

Hayashi, Chushiro, “Formation of the Planets,” in Fundamental Problems in the Theory of Stellar Evolution, Proceedings of IAU Symposium No. 93, Kyoto, Japan, July 22-25, 1980 (D. Reidel, Dordrecht, 1981), pp. 113-126; Discussion, p. 127, 128.

Hayashi, Chushiro, “General Discussions — Fundamental Problems in the Theory of Stellar Pulsation,” in Fundamental Problems in the Theory of Stellar Evolution, Proceedings of IAU Symposium No. 93, Kyoto, Japan, July 22-25, 1980 (D. Reidel, Dordrecht, 1981), pp. 339-42.

Hayashi, Chushiro, “Structure of the Solar Nebula, Growth and Decay of Magnetic Fields and Effects of Magnetic and Turbulent Viscosities on the Nebula,” Progr. Theoret. Phys. Supp. 70, 35-53 (1981).

Nakagawa, Yoshitsugu, Kiyoshi Nakazawa, & Chushiro Hayashi, “Growth and Sedimentation of Dust Grains in the Primordial Solar Nebula,” Icarus 45, 517-28 (1981).

Hayashi, Chushiro, Shinji Narita, & Shoken M. Miyama, “Analytic Solutions for Equilibrium of Rotating Isothermal Clouds — One-Parameter Family of Axisymmetric and Conformal Configurations,” Progr. Theoret. Phys. 68, 1949-66 (1982).

Nakagawa, Yoshitsugu, Chushiro Hayashi, & Kiyoshi Nakazawa, “Accumulation of Planetesimals in the Solar Nebula,” Icarus 54, 361-76 (1983).

Miyama, Shoken M., Chushiro Hayashi, & Shinji Narita, “Criteria for Collapse and Fragmentation of Rotating, Isothermal Clouds,” Ap.J. 279, 621-32 (1984).

Miyama, Shoken M., Chushiro Hayashi, & Shinji Narita, “Characteristics of Collapse of Rotating Isothermal Clouds,” Progr. Theoret. Phys. 72, 1118-36 (1984).

Hayashi, Chushiro, Kiyoshi Nakazawa, & Yoshitsugu Nakagawa, “Formation of the Solar System,” in Protostars and Planets II (University of Arizona Press, Tucson, 1985), pp. 1100-53.

Nakagawa, Yoshitsugu, Minoru Sekiya, & Chushiro Hayashi, “Settling and Growth of Dust Particles in a Laminar Phase of a Low-mass Solar Nebula,” Icarus 67, 375-90 (1986).

Hayashi, Chushiro, “Equilibria and Dynamics of Isothermal Clouds,” in Star forming regions; Proceedings of IAU Symposium 115, Tokyo, Japan, Nov. 11-15, 1985 (Reidel, Dordrecht, 1987), pp. 403-416.

Kiguchi, Masayoshi, Shinji Narita, Shoken M. Miyama, & Chushiro Hayashi, “The Equilibria of Rotating Isothermal Clouds,” Ap.J. 317, 830-45 (1987).

Sekiya, Minoru, Shoken M. Miyama, & Chushiro Hayashi, “Gas Flow in the Solar Nebula Leading to the Formation of Jupiter,” Earth, Moon, and Planets 39, 1-15 (1987).

Miyama, Shoken M., Shinji Narita, & Chushiro Hayashi, “Fragmentation of Isothermal Sheet-Like Clouds,” Progr. Theoret. Phys. 78, 1051-64 (1987) and 78, 1273-87 (1987).

Kiguchi, Masayoshi, Shinji Narita,Shoken M. Miyama, & Chushiro Hayashi, “The Equilibrium and the Stability of Rotating Isothermal Clouds,” Progr. Theoret. Phys. Supp. 96. 50-62 (1988).

Narita, Shinji, Shoken M. Miyama, Masayoshi Kiguchi, & Chushiro Hayashi, “Collapse and Fragmentation of Isothermal Clouds,” Progr. Theoret. Phys. Supp. 96. 63-72 (1988).

Sekiya, Minoru, Shoken M. Miyama, & Chushiro Hayashi, “Gas Capture by Proto-Jupiter and Proto-Saturn,” Progr. Theoret. Phys. Supp. 96. 274-80 (1988).

Narita, Shinji, Masayoshi Kiguchi, Shoken M. Miyama, & Chushiro Hayashi, “Rotation-dominant Equilibria of Isothermal Clouds,” MNRAS 244, 349-56 (1990).

Narita, Shinji, Masayoshi Kiguchi, & Chushiro Hayashi, “The Structure and Evolution of Thin Viscous Disks. 1: Non-Steady Accretion and Excretion,” Pubs. Astr. Soc. Japan 46, 575-87 (1994).

Kiguchi, Masayoshi, Shinji Narita, & Chushiro Hayashi, “Wind from T Tauri Stars,” Pubs. Astr. Soc. Japan 50, 587 (1998).

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