Astro 160: The Physics of Stars

which seems rather odd, We would expect this main sequence He buring star to be above the mainsequence line. This can be explained by our initial assumption that went into deriving this relationship.We assumed that this was a pure ball of He gas.e) At what mass does the luminosity of the star exceed the Eddington luminosity?We know that the Eddington luminosity is given byL Edd = 4πcGMκL f usion = 42.7L sun( MM sun) 3setting these two expressions equal to each other givesgiven the opacity defined asthus4πcGM sunκ( MM sun)= 42.7L sun( MM sun) 3κ = n eσ Tρn e =ρµ e m pκ = 1µ e m pσ T µ e = 2 κ = σ T2m p≈ 0.2 g/cmM ≥ 38.95M sunis the mass that will exceed the Eddington luminosityf ) What is the He main sequence lifetime as a function of stellar mass? Compare this to the correspondingH burning lifetime.50