. after the helium flash, the sun will settle onto the horizontal branch in the h-r diagram. there it is stably burning helium in its core. assume that the helium burning dominates the luminosity of the star (over the h shell burning), and that the luminosity of the sun on horizontal branch is 50 l . further assume that the core is 10% of the mass of the star. for approximately how long can the sun burn he in its core
