Proton-Proton Reactions in Red Dwarf Stars.

Abstract

view Abstract Citations (5) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Proton-Proton Reactions in Red Dwarf Stars. Aller, Lawrence H. Abstract The relative roles of the carbon cycle and of proton-proton reactions in red dwarf stars such as Krueger 60A and Oi Eridani C are studied with the aid of models calculated by Schwarzschild and Keller, in which the heavy stuff is taken as the Russell mixture and as oxygen, respectively. The proportions of carbon- . plus-nitrogen are taken as 0.08 and 0.15 for the RM and 0 models, respectively. The lifetime of the carbon cycle, taken from recent work at the California Institute of Technology, is 106 years for p = 80 gm/cm3, T = 20,000,000 K, and hydrogen content X = 0.35. The adopted value of the Fermi constant is 1.13 X 10- . Our is to find a pair of X (hydrogen content) and Y (helium content) values that satjsfy the mass-luminosity relation for the model and for which observed and calculated energy outputs are equal. For the Russell mixture, two solutions are possible. In one, 60-70 per cent of the energy comes from the carbon cycle, and the balance is supplied by the proton-proton reaction. In the second solution all the energy is contributed by the proton-proton reaction. For Krueger 60A, X = 0.11, Y = 0.64, T = 15,400,000 K, with 60 per cent of the energy supplied by the carbon cycle; or, alternatively, X = 0.34, Y = 0.64, and T = 10,700,000 K, with proton-proton reactions delivering all of the energy. Stellar models in which the heavy material is all oxygen are always too bright. No emphasis can be placed on the actual X and Y values, since the opacity law assumed for the sun cannot apply in red dwarfs, nor are the models valid when energy generation occurs outside the convective core. If further work shows that the composition approaches that of the oxygen model, it may be necessary to assume a structure consisting of two zones of different molecular weight. Publication: The Astrophysical Journal Pub Date: January 1950 DOI: 10.1086/145248 Bibcode: 1950ApJ...111..173A full text sources ADS | data products SIMBAD (2)