The Sun has a diameter of 1.4 million kilometers. Convert this to pc (1 pc = 3.26E13 km). Compare this to the size of the planetary nebula you calculated above. Which is larger? What is the cause of the difference in sizes?
2. Compare the size of a planetary nebula to the size of a supernova remnant. Which is larger? What do you think is the cause of the difference in sizes? (Hint: review how each of these are formed.)
3. Find the density of a typical white dwarf of mass 1.0 solar masses and radius 6000 km, in g/cm3. Remember that 1 solar mass is 2E33 g, 1 km is 1E5 cm, and the volume of a sphere of radius r is 4/3 π r^3. (Hint: It helps to first calculate the volume of the white dwarf, then use this value in the equation for density.) Compare your answer to the density of water = 1 g/cm3.
This is what was given to me by my instructor. I don't know what to do.