Prog. Theor. Phys. Vol. 34 No. 6 (1965) pp. 885-911

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Advanced Phases of Evolution of Population II Stars

— Growth of the Carbon Core and Shell Helium Flashes —

Chushiro Hayashi, Reiun Hōshi and Daiichiro Sugimoto^*

Department of Physics, Kyoto University, Kyoto
^*Department of Physics, Nagoya University, Nagoya

(Received August 3, 1965)

Abstract:

As the extension of our previous work, calculations have been made of the evolution of a population II star after the formation of a carbon core. We start from a stage when the star has an inactive hydrogen shell-source, a helium-burning shell-source and a partially-degenerate isothermal carbon core. The luminosity due to shell helium-burning attains a maximum value, 1.6×10³ L_⊙, when the core mass grows to 0.47 M_⊙. After this stage, helium-burning decays rapidly while the hydrogen shell-source becomes active.
In the next phase the mass of the helium grows through shell hydrogen-burning and the inner layers of the helium zoen begin to be degenerate. The gravitational contraction of the helium zone gives rise to the heating of the helium shell-source, until the second helium flash sets in at the degenerate shell when the mass interior to the hydrogen shell-source becomes 0.61 M_⊙.
The subsequent evolution is, in general, the repetition of the preceding phases. The third helium flash sets in when the mass interior to the hydrogen shell-source becomes about 0.7 M_⊙ and the luminosity is about 8×10³ L_⊙.

URL : http://ptp.ipap.jp/link?PTP/34/885/
DOI : 10.1143/PTP.34.885

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Citing Article(s) :

Progress of Theoretical Physics Vol. 36 No. 1 (1966) pp. 17-36 :
Second Helium Flash and an Origin of Carbon Stars

Daiichiro Sugimoto and Yoshiaki Yamamoto
Progress of Theoretical Physics Vol. 36 No. 3 (1966) pp. 504-514 :
Central Temperature and Density of Stars in Gravitational Equilibrium

Katsuo Takarada, Humitaka Sato and Chushiro Hayashi
Progress of Theoretical Physics Vol. 39 No. 4 (1968) pp. 957-984 :
Thermal Instability in a Nuclear-Burning Shell of Stars

Reiun Hōshi
Progress of Theoretical Physics Vol. 48 No. 6 (1972) pp. 1870-1884 :
Stellar Evolution toward Pre-Supernova Stage. II

Satoru Ikeuchi, Kiyoshi Nakazawa, Tadayuki Murai, Reiun Hōshi and Chushiro Hayashi