Hydrogen core compositional model

Figure 4. The temperature in units of 1000 K is given as a function of Lagrangian mass for models with L = 55,000 L , Teff = 15,500 K, R = 33.4 R and envelope composition X = 0.7, Y - 0.295, Z = 0.005, fora range of total masses. This luminosity corresponds to original main sequence mass of about 15 M and a helium core mass of 4 M . Note that for smaller total mass and hence smaller envelope mass the temperature rises rapidly to exceed the hydrogen ignition temperature well outside the core.

Fig. 8. The composition profile for the C, N, and O isotopes as a function of the interior mass for the 1M and 3M Z = 0.02 models. The unit on the y-axis is the logarithm of the number fraction, Y, where the mass fraction is given by X = YA, and A is the atomic mass. The composition profile is a snap-shot of the interior composition of the star at an instant in time, in this case at the end of core hydrogen exhaustion...

Seth and Ross [17] studied the reduction of ferric oxide composites by hydrogen and used a shrinking-core model to interpret their results. Figure... 

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