Transcript: After the main sequence the core and the envelope of a star often follow utterly different evolutionary paths. For example consider the fact that in a red giant the outer envelop becomes cooler than the Sun, or redder, while the core is actually more than ten times hotter. Remember also that when we observe stars in the sky we are only every seeing the photospheric temperature reflecting the color and the energy in the outer diffuse envelope. Often the conditions in the deep core of the Sun or any other star are vastly different. Material can also be lost into space during stellar evolution so the final mass of a star or a stellar remnant is always less than the initial mass.