Model for Pre-Supernova Stars.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Model for Pre-Supernova Stars. Chiu, H. Y. Abstract When the internal temperature of a star exceeds 10 0K the evolution is very rapid (H. Y. Chin and P. Morrison, Phys. Rev. Letters 5, 573,1960). The time scale is around 3000 years. Energy dissipated by emission of neutrinos is several orders of magnitude higher than that by optical radiation. Neutrinos have exceedingly long mean free path ( 1020 gcm2) and they will escape as soon as they are produced. The star will contract to release gravitational energy to make up the energy lost to neutrinos and the internal temperature will rise to comply with the virial theorem. It is possible in this fast evolutionary phase to neglect optical radiations altogether as compared with the neutrino radiation. Then the equations of the core are much simplified. A simple model has been constructed and analytical solutions obtained. The resulting star becomes a supernova via the iron- helium transition mechanism as suggested by Burbidge et al. (Burbidge, E. M., Burbidge, G. K., Fowler, NV. A., and Hoyle, F., Revs. Modern Phys. 29, 547,1957). The model consists of a perfect gas sphere and a neutrino energy loss function of the type d Udt = - U0 T (in ergs$g-sec), where U is the internal energy per gram of matter and U0 is a constant; T is the temperature. Initially the star has the structure of a polytropic gas sphere of index 1.5. The star evolves into a supernova via homologous transformations. This property is a result of our simplified neutrino energy loss function, and is not likely possessed by the actual star. The general case will be studied on a computer. Publication: The Astronomical Journal Pub Date: March 1961 DOI: 10.1086/108544 Bibcode: 1961AJ.....66R.280C full text sources ADS |