How do I combine...

[PlutonianEmpire]

...the brightnesses and gravity of two stars into one?

Code: Select all

200010 "Binaria A" {
   SpectralType "G8V"
   AbsMag 5.078

   OrbitBarycenter "Binaria"

   EllipticalOrbit {
      Period             ???
      SemiMajorAxis      0.021863738285054992859912427535
      Eccentricity       0.000
      Inclination        0.000
      AscendingNode      0.000
      ArgOfPericenter    0.000
      LongitudeNode      0.000

   }
}

and

Code: Select all

200011 "Binaria B" {
   SpectralType "G9V"
   AbsMag 6.650

   OrbitBarycenter "Binaria"

   EllipticalOrbit {
      Period             ???
      SemiMajorAxis      0.065591214855164978579737282605
      Eccentricity       0.000
      Inclination        0.000
      AscendingNode      0.000
      ArgOfPericenter  180.000
      LongitudeNode      0.000
   }
}

And no, I came up with a number for the period, obviously, so celestia doesn't screw up by accident.

The reason i'm asking is because i'm using rassilon's ssc code generator to try to portray accurate orbital periods for the different planets I have floating around in my plutonian empire universe on celestia.

Here's an old screenshot of it:

[selden]

Celestia does not yet add luminosities properly to calculate the temperature of objects orbiting in binary systems, if that's what you want.

When calculating gravitational effects, you can just add the masses of the two stars and treat them as one. The exact orbital motions in a system with more than one star can be extremely complicated. Celestia doesn't even try to calculate them.

[PlutonianEmpire]

Well, how do i figure out the masses of two fictional stars, such as the pair above?

[bdm]

Well, how do i figure out the masses of two fictional stars, such as the pair above?

That depends on the spectral types of the stars. You would do well to consult tables of spectral types, which often have masses with them. The mass you want is the mass of the star in solar masses. A planet orbiting a 1-solar mass star at a distance of 1 A.U. has a period of 1 year. The period of a planet of small mass around a star is inversely proportional to the square root of the mass of the star.

P = 1/(M^0.5)

Here is a good table for nearby stars.
http://www.nfbcal.org/~gnordley/Nearby% ... mmary.html

[selden]

One summary of spectral classes and masses is at http://outreach.atnf.csiro.au/education/senior/astrophysics/spectral_class.html
.