1) Fusing hydrogen to helium converts 0.7% of the rest mass energy of the hydrogen to radiation. Using
the masses and luminosities in the chart on page 10 of the stellar classification notes, estimate the
lifetime for stars of the following spe
1) 25 points What are the spectral types of the three stars below? Credit will be given for +/- one type
in either direction.
O, G, M
2) The figure below shows Rosseland mean opacities as a function of temperature for several densiti
Homework 5: Compact objects and extrasolar planets
1) There is a one earth mass planet orbiting an M5 star of 0.2 M and luminosity 1x10-2 L.
A) How close does the planet need to be to the star in order to receive the same amount of energy
as the Earth
Homework 4: Massive star deaths
1) The energy per gram produced by fusion is similar for He, C, and O burning. However, the rate of
neutrino losses increases markedly. Assume that for each of these burning stages the energy per gram
of material released i