Abstract
An evolutionary model of a Population I star of 20M ⊙ and of compsitionX=0.70;Y=0.28, beyond the main sequence and up to core helium exhaustion is reported. Calculations were carried out to determine the effect of semi-convection using a method of mixing considered physically more appropriate than previous methods. Both the density as wel as the temperature stability criteria were employed in parallel calculations and reasons are advanced to prefer the temperature criterion. The results of the model calculations reported here underline the importance of the proper choice of the stability criterion and an appropriate mixing-scheme. In addition it is demonstrated that the loop phenomenon seen in the helium burning evolution of less massive stars is either absent or very unpronounced at 20M ⊙.
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References
Barbaro, G., Chiosi, C., and Nobili, L.: 1972,Astron. Astrophys. 18, 186.
Chiosi, C. and Summa, C.: 1970,Astrophys. Space Sci. 8, 478.
Cox, A. N. and Stewart, J. N.: 1965,Astrophys. J. Suppl. 11, 22.
Cox, J. P. and Giuli, R.: 1968,Principles of Stellar Structure, Gordon and Breach, N.Y.
Eggleton, P.: 1971,Monthly Notices Roy. Astron. Soc. 151, 351.
Eggleton, P.: 1972,Monthly Notices Roy. Astron. Soc. 156, 361.
Hack, M.: 1971,Proc. Trieste Colloq. Supergiant Stars, Osservatorio Astron. Trieste (see review by N. Dallaporta. p. 250).
Iben, I.: 1966,Astrophys. J. 143, 91.
Iben, I.: 1967,Ann. Rev. Astron. Astrophys. 5, 571.
Kato, S.: 1966,Publ. Astron. Soc. Japan 18, 374.
Ledoux, P.: 1947,Astrophys. J. 105, 305.
Paczynski, B.: 1969, private communication.
Paczynski, B.: 1970,Acta Astron. 20, 47 and 195.
Robertson, J. W.: 1973,Astrophys. J. 177, 473.
Robertson, J. W. and Faulkner, D. J.: 1972,Astrophys. J. 171, 309.
Sakashita, S. and Hayashi, C.: 1958,Progr. Theor. Phys. 22, 830.
Sakashita, S. and Hayashi, C.: 1961,Progr. Theor. Phys. 26, 942.
Schlesinger, B.: 1971,Bull. Am. Astron. Soc. 3, 394.
Schwarzschild, M.: 1970,Quant. J. Roy. Astron. Soc. 11, 12.
Schwarzschild, M. and Härm, R.: 1958,Astrophys. J. 128, 348.
Simpson, E.: 1971,Astrophys. J. 165, 295.
Sreenivasan, S. R. and Ziebarth, K. E.: 1971,Bull. Am. Astron. Soc. 3, 394.
Sreenivasan, S. R. and Ziebarth, K. E.: 1972,Bull. Am. Astron. Soc. 4, 240.
Stothers, R.: 1969,Astrophys. J. 155, 935.
Stothers, R.: 1970,Monthly Notices Roy. Astron. Soc. 151, 65.
Stothers, R. and Chin, C.: 1968,Astrophys. J. 152, 225.
Stothers, R. and Chin, C.: 1969,Astrophys. J. 158, 1039.
Stothers, R. and Chin, C.: 1973a,Astrophys. J. 179, 555.
Stothers, R. and Chin, C.: 1973b,Astrophys. J. 180, 901.
Ziebarth, K. E.: 1970,Astrophys. J. 162, 947.
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Sreenivasan, S.R., Ziebarth, K.E. The post-main sequence evolution of a star of 20M ⊙ to core helium exhaustion. Astrophys Space Sci 30, 57–70 (1974). https://doi.org/10.1007/BF00645753
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DOI: https://doi.org/10.1007/BF00645753