Making Binary Orbits

[Dan Dixon]

A user of Universe Sandbox wrote in asking:

I'm having a little trouble making my universe behave!

... [I want to setup] a system with two suns. One is the existing sun, and the other is a planet that contracts and turns into a sun (like the theory surrounding Jupiter eventually becoming a brown dwarf)

I was hoping to tilt the planet so that the new sun is only ever visible from one portion of the planet. I was also toying with the idea that the new sun orbits a black hole, making it invisible when the black hole orbits between the planet and the new sun.

So far all I've been able to do is make two suns crash into one another and the planet and remaining sun shoot off into space.

Forgive me if my explanation is confusing! I am new to this.

Thanks for your questions.

It's good to hear about what is confusing and needs improvement in Universe Sandbox. It's not yet as clear as it could be. Some incremental improvements to this will come in version 2.0.4.

So far all I've been able to do is make two suns crash into one another and the planet and remaining sun shoot off into space.

Here's a post that shows how to make 3 stars orbit each other using the binary orbit tool:
http://universesandbox.com/forum/index.php/topic,1026.0.html

For just 2 stars:

1 - Go into edit mode or pause the simulation.
2 - Add two stars
3 - Select both stars and click the "Binary Orbit" button, only visible once both bodies are selected.

...the other is a planet that contracts and turns into a sun (like the theory surrounding Jupiter eventually becoming a brown dwarf)

Cool idea... Although realistically, Jupiter would have to gain about 80x its mass to begin nuclear fusion and become a star.

http://www.badastronomy.com/bad/misc/jupiter_galileo.html
See Point #3 (scroll down on this page)

I was also toying with the idea that the new sun orbits a black hole, making it invisible when the black hole orbits between the planet and the new sun.

Orbiting a black hole is a cool idea, but a black hole even 100 times the mass of our Sun would only have a diameter of 591 km (you can see this in the upcoming 2.0.4 version).
http://en.wikipedia.org/wiki/Schwarzschild_radius
... which isn't a very big object to block out another sun.