Imagine that the Sun will end its main sequence with a pure He core of 0.25 Msun, and that core has a radius of 0.2 Rsun. Derive an expression to estimate the time it will take that core to contract to a radius of 0.02 Rsu n, at which point its contraction is halted by degeneracy pressure. The estimate that time in years, assuming a constant L=Lsun and alpha=0.5