Radiation Pressure, part 1.
Calculate the Eddington Luminosity for a 120 $M_\odot$ star with Hydrogen mass fraction of
X = 0.7. In this case, assume the opacity is due to electron scattering only (which is
reasonable because all the Hydrogen will be ionized in the star).
Give your answer in Solar Luminosities, where 1 Solar Luminosity = 3.84 × 10$^{26}$ W.
1.6e3 Solar Luminosities
1.8e33 Solar Luminosities
2.3e-34 Solar Luminosities
7.8e4 Solar Luminosities
3.8e5 Solar Luminosities
4.6e6 Solar Luminosities
Radiation Pressure, Part 2.
What is the approximate luminosity for a main-sequence star with a mass of 120 $M_\odot$ star?
Hint: Refer to figure 10.13 in your textbook.
4.5e2 solar luminosities
6 solar luminosities
1.8e6 solar luminosities
120 solar luminosities
Radiation Pressure, Part 3.
(You will need to have finished Radiation Pressure, Parts 1 and 2 to complete this question, go
back and do that first if you have not yet done so!)
For the 120 $M_\odot$ star, compare your answers for the Eddington Luminosity and star's actual
luminosity. Do you expect radiation pressure to be significant for a 120 $M_\odot$ star?
No, the Eddington Luminosity is much, much greater than the Star's Luminosity, so Radiation Pressure
will not be important for this star.
No. the star's luminosity is much, much higher than the Eddington Luminosity, so Radiation Pressure
will not be important.
There is no way to tell.
Yes, the Eddington Luminosity is comparable to the star's actual luminosity, so the radiation pressure
will be important.
