| 01. | (a) Find the average density of a 1-M⊙ white dwarf having the same diameter as the Earth. (b) What speed is required to eject gas from the white dwarf's surface? (This is also the speed with which interstellar gas falling from a great distance would strike the star's surface.) |
| 02. | (a) What kinds of stars would you monitor if you wished to observe a supernova explosion from its very beginning? (b) Examine Appendices 4 and 5, which list the nearest and brightest stars, respectively. Which, if any, of these stars are possible supernova candidates? Explain. |
| 03. | Suppose that the red-supergiant star Betelgeuse, which lies some 1400 light-years from the Earth, becomes a Type II supernova. (a) At the height of the outburst, how bright would it appear in the sky? Give your answer as a fraction of the brightness of the Sun (b⊙). (b) How would it compare with the brightness of Venus (about 10-9 b⊙)? |
| 04. | In July 1997, a supernova named SN 1997cw exploded in the galaxy NGC 105 in the constellation Cetus (the Whale). It reached an apparent magnitude of +16.5 at maximum brilliance, and its spectrum showed an absorption line of ionized silicon. Use this information to find the distance to NGC 105. (Hints: Inspect the light curves of SNe to find the absolute magnitudes of typical supernovae at peak brightness.) |
