Alpha Centauri/Trisolaris Orrery

Alpha Centauri/Trisolaris Orrery

The Alpha Centauri system has 3 stars. The 2 larger stars orbit about a common center while the 3rd star orbits at a much greater distance. There are no known planets orbiting the central 2 stars. There is at least one and possibly 3 planets orbiting the more distant red dwarf (Proxima Centauri). The second planet has been disputed and the third is unconfirmed. I’ve designed three versions to accommodate all three possibilities. Trisolaris from the book The Three Body Problem has only one planet. While there is no general solution to the three body problem, there are a few known special cases. With the extreme distance (13,000 AU or 0.21 ly) of the 3rd star, this system is very stable for the long term. I also wonder if Proxima Centauri could be the red star in 2112?

Nothing about this model is to scale spatially or temporally. The relative distances are just too great.

There are 2 different bases. One with a hand crank and another which can be motorized using a small hobby gear motor such as this found on amazon, You will also need a battery holder for 2 AA cells and a small SPST toggle switch as well as some small fasteners. Check the bill of materials in the instructions for the motorized base for a complete list. Separate instructions for each base option are included. If you go with the standard base, the model is fully 3D printable. First decide which base you want for your model. Then go to the instructions for that base and build it. Then go to the instructions for which version of the orrery you want to go with that base, and follow those instructions for the rest of the build.

Everything can be printed in PLA with a 0.4 nozzle with a layer height of 0.2 mm with a few exceptions which will be noted. A small amount of CA glue or other glue that works with plastic will be needed.

This is a bit more advanced than most printed models. Tolerances are fairly tight. I found that if there is too much play between the parts, they may bind. Check the fit of the parts before final assembly to make sure that the parts that are supposed to move freely do so. Some light filing will be needed. Where glue is used, glue sparingly and do not allow the glue to spread to other parts or mating surfaces. This is a project where reading all of the instructions before starting is highly recommended. There are 6 different variations that can be built depending on how many planets you want and whether you want the base to be motorized or hand powered.

Note the final versions of some of the parts may vary a bit in appearance from what is shown in the instructions. I skeletonized the base and gear train arm to reduce the amount of plastic used.

PS I painted a set of stars and planets with fluorescent paint and illuminated the system with a UV LED with the lights off. Looked really cool.

Detailed instructions are in the files.