[TML] Planets in binary systems

[Timothy Little]

On Mon, Mar 03, 2008 at 05:34:04AM -0500, Jerry W Barrington wrote:
> Well, I couldn't quite follow some of your substitutions.  You said
> "R = (1 - u) r1, so that u is the ratio between L1 distance from the
> smaller body and that body's orbital radius", but that seems to call
> for R=u*r1.

R is the distance between L1 and the barycentre of the system, not the
distance between body 1 and L1.


> Since Goal Seek seems have a rather arbitrary precision, I found
> that multiplying the entire formula by 100,000 made it find the
> correct value for equal masses, .50..., instead of 0.50017933232343
> or 0.499999986081074.

Yes, spreadsheets aren't exactly the best tools for precision
mathematical analysis.


> I suspect since the Hill formula is only an approximation anyway, my
> values are better.  And they're smaller, and I'm only going to use
> 2/3 to 1/2 of *that* value, so it's all good.  :)

Yes, extreme precision isn't really necessary when it's going to be
divided by some rough factor later :-)


- Tim