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Find the radii of the two stars

by leonne
Tags: radii, stars
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Oct6-10, 01:25 PM
P: 192
1. The problem statement, all variables and given/known data
From the light and velocity curves of an eclipsing, double-lined spectroscopic binary
star system, it is determined that the orbital period is 3.15 yr, and the maximum radial
velocities of stars A and B are 5.2 km s^-1 and 21.6 km s^-1, respectively. Furthermore,
the time between first contact and minimum light is tb-ta = 0.45 days, while the length
of the primary minimum is tc -tb = 0.52 days. Relative to the maximum brightness,
the primary minimum is only 54.8% as bright, while the secondary minimum is 88.1%
as bright
You may assume the orbits are circular and seen perfectly edge on.

Find the ratio of the stellar masses (mA/mB), the sum of the masses (M =
mA + mB), and the individual masses (mA and mB).
(b) Find the radii of the two stars. Hint: Use the speed of one star relative to the
other and the eclipse timings given.

2. Relevant equations
v1=(2pie a1)/p r=a(1-e^2)/(1+ecos@) m1=(4V1^2*r1)/G

[c]3. The attempt at a solution[/b]
so becasue its edge on that means inclination angle is 90degrees so thats the real velocity and e = 0 too so just use these formula to find masses right?
now for part B would i just the formula r=a(1-e^2)/(1+ecos@) to find the radii? checked in book showed this as radii but hint says to use something different i think
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Oct6-10, 02:35 PM
P: 192
nvm i think i figured it out

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