(i) The Hertzsprung-Russell diagram illustrates the evolution of stars.
- Sketch the main features of the diagram, label the axis and indicate the present position of the Sun.
- Referencing your diagram, explain briefly the evolution of the Sun from present to the white dwarf stage.
(ii) The surface temperature of the Sun, Ts, is 5780 ‡ 20 K, and its mean radius, ro, is 6.95 x 10^8 ‡ 0.01 x 10^8 m.
- Assume that the surface of the Sun radiates like a perfect blackbody and calculate the Sun's current luminosity, including estimating the error.
- At some point in the future the Sun will start to expand into interplanetary space. Assuming that the Sun's luminosity remains unchanged, what will the Sun's new surface temperature be when its radius has expanded to double its current value? You do not need to estimate error for this part