# Tag Info

From this webpage, I have a few statistics regarding required density and temperature to burn a specific element. Burning phase; Required temperature; Required mean density; Duration Hydrogen burning: $4 \times 10^7 \text{ degrees K; } 5 \text{ gm per cubic cm; } 7,000,000 \text{ years}$ Helium burning: $2 \times 10^8 \text{ degrees K; } 700 \text{ gm ... 1 This is only a rough estimate. But the number of supernovae in the Milky Way is approximately 2-5 / 100 years (here and here). There is approximately$3 \times 10^{11}$stars in the Milky Way. Provided the supernovae rate did not change much through the history (which is a big if that probably doesn't work), the total number of supernovae would be ... 1 I'm no expert on stellar atmospheres, so I have a limited idea of how things like$\log g\$ affect the lines. But I work with stellar models, so I can take a stab at that part. The overall principle is that computing stellar model ages is a kind of optimization problem. We model the structure of stellar interiors by constructing a system of differential ...