Have you always dreamed of building your own planet? Or perhaps your own Death Star? Well, here are good news for you: there may be plenty of potential orbits out there that could host it.
For a planetary system to be stable, stars and planets must be spaced at specific distances: the gravitational forces at play must be such that the system holds together stably, allowing planets to follow their orbits without colliding or being ejected.
In a study published in April in The Astrophysical Journal, two researchers at the University of California, Los Angeles, tested the hypothesis that all stable planetary systems are filled to capacity, that is, that every possible orbit in a gravitationally stable system is indeed occupied by a planet. To do so, they used computer simulations of planetary systems and data from actual observations by the Kepler telescope. Their results indicate that many planetary systems are indeed “dynamically packed”, as they put it, but also that there may be some planetary systems that have vacant orbits where a new planet could be added without messing up the global gravitational stability of the system.
However, as another astrophysicist told New Scientist in a news story about this study, discovering a stable but unoccupied orbit in a planetary system may also just mean that there is another planet in there, but that it has not been detected yet.
But let’s imagine for a moment that you find such an orbit, and that it’s truly vacant: you could theoretically build your own planet there, without having to worry about destroying the gravitational stability of the whole system – well, at least not for the next 100 million years (that’s the time period the researchers covered when they modeled how the different planetary orbits of a given system would evolve after the insertion of a new planet).
If you’re planning on introducing life onto this new planet you’re building, you may also want to make sure the orbit you choose is in the Goldilocks zone of its star (if you’re importing life such as we know it on Earth of course, otherwise it might not matter that much).
But then, that’s it, you’re good to go.
You just need to figure out the logistics of the whole thing now.
Are planetary systems filled to capacity? A study based on Kepler results. Julia Fang and Jean-Luc Margot. 2013 ApJ 767 115. doi:10.1088/0004-637X/767/2/115