Rogue (starless) planet method?

[Mneme]

What would be the most efficient way to make a rogue planet with a path through interstellar space?

I have tried having the planet orbit a star at great distance, but the planet then becomes invisible. Likewise orbiting a ReferencePoint itself orbiting a star.

What might work?

[selden]

Unfortunately, Celestia doesn't directly support the drawing of rogue planets.

One way to fake it is to define a tiny star and a much larger planet. Specify a tiny SMA for the planet, so the star is always inside the planet. The planet's surface illumination will look like there's an external star, though.

Another way is to define the planet as if it were a Nebula. It'll have a uniform surface illumination, but it won't be able to move.

[omega13a]

You could have the planet follow a very hyperbolic path around a star (like an eccentricity greater than 5.0). Since its following a hyperbolic path, it technically isn't orbiting anything.

[Mneme]

Sounds good. I'll probably have to do the tiny star for lighting and temperature and have that orbit a dummy star in the center of the populated region, or maybe at the galactic center. Thanks folks.

[omega13a]

Just be sure to use PericenterDistance for a hyperbolic orbit and not SemiMajorAxis. If you use SemiMajorAxis, you get one weird orbit as I found out the hard way. Also, the orbital period for a hyperbolic orbit has a different fomula than an elipitical one. See http://en.wikibooks.org/wiki/Celestia/SSC_File#Period_f for details.