A 0.7 MO star on the horizontal branch has a radius of 10 RO and a surface temperature of 4500 K (Where MO is the mass of the sun and RO is the Radius of the Sun). The He-burning core is 10% of the mass of the star. Given that the He4 nucleus has a mass of 4.00260324 atomic mass units (a.m.u.) and the C12 nucleus has a mass of 12.00000000 a.m.u. estimate the maximum length of time the star could conceivably spend on the horizontal branch