1. Why are there many more Main-Sequence stars than Red Giants ? 2. What is the source of energy in a white dwarf star ? 3. How can a supernova continue to shine many years after it has exploded ?
i) Briefly explain why a star of mass 0.5A/1,, collapses to form a white dwarf when the nuclear reactions in its core cease. (ii) That is the maximum theoretical mass of a white dwarf? Describe (in about 100 words) what happens to a star if its mass exceeds this value. (iii) What is the maximum theoretical mass of a neut
Do we know where cosmic rays come from? If so, what are some of the sources? Do we know all of them?
A pulsar is a rapidly rotating neutron star that continuously emits a beam of radio waves in a searchlight manner. Each time the pulsar makes on revolution, the rotating beam sweeps across the earth, and the earth receives a pulse of radio waves. For one particular pulsar, the time between two successive pulses is 0.033 s. What