Celestia Forums

When building close binaries in Celestia, what SIMPLE formulas can I use for planets orbiting them?

For example, how much shorter would a planet's orbital period be around two stars of equal mass than it would around a single star of the same mass, and how much farther would an Earth-mass planet need to be from the two stars in order to protect living beings on it than it would around the single star?

Unfortunately, although they're analytically solvable, 3body problems aren't all that simple.
I'd suggest working with very tight pairs, so you can treat them as if they were single stars with twice the mass and twice the luminosity.

selden wrote:Unfortunately, although they're analytically solvable, 3body problems aren't all that simple.
I'd suggest working with very tight pairs, so you can treat them as if they were single stars with twice the mass and twice the luminosity.

Yeah, um, I'm afraid I don't know how to do that. Sorry. (Although I might be able to use Gravity Simulator to help me out with the orbit times.)

EDIT: What about rule of thumbs? Are there any rule of thumbs I can follow?

"factor of two" = "rule of thumb"

In other words, treat them as a single star which is twice as massive and twice as bright. (A star that was twice as massive would actually be more than 15x as bright.)

Use http://www.geocities.com/albmont/mseqstar.htm

Ok, thank you.