Consider a 1 M _$\odot$ Star's Journey Up the Red Giant Branch

Essay

Consider a 1 M _$\odot$ star's journey up the red giant branch. Its luminosity will change from 10 L _$\odot$ to nearly 1,000 L _$\odot$ . How will its temperature and radius change as the star ascends? (Recall that L $\infty$ R²T ⁴.)