On the evolution of obstars from the main sequence to the Helium exhaustion phase |
| |
Authors: | C. Chiosi C. Summa |
| |
Affiliation: | (1) Istituto di Fisica e Istituto di Astronomia dell'Università, Padova, Italy |
| |
Abstract: | The evolution of a 20M star of extreme Population I (X=0.602,Z=0.044) from the main sequence through the He-exhaustion has been calculated with particular attention to the treatment of the semiconvective zones. Two different relations as convective instability criteria have been adopted Ra+(/(4–3)) (d ln /d lnP) or Ra). The He-burning phase is substantially different in the two cases. In the first evolutionary picture the star begins the He-burning phase as red supergiant, while in the second one as blue supergiant. The two evolutions are compared with the observational blue to red supergiants rationB/nR in connection with the problem of the existence of the neutrino processes and taking into account the possible presence of a high percentage of binary systems among supergiants.We draw the conclusion that the massive star evolution seems to be still completely uncertain and also not able to give a decisive test for or against the neutrino emission. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|