Hi Francisco,
> Please forget my message. Finally yesteday I could confirm that "gm"
> variable is G * (Ma + Mb)
True. I'm usually thinking in terms of asteroids, where the
mass of the secondary component can be safely neglected (unless
you're going out to ten decimal places... which doesn't seem so
outrageous, now that I think of it.) I've never tackled solving
binary star orbits. But converting a state vector to classical
elements ought to work the same way.
-- Bill