Are there any unconfirmed planets in our solar system?
Planet 9 is an unconfirmed planet in our solar system.
There is evidence to suggest that there is an as yet undiscovered large planet in the outer solar system. This planet is currently referred to as Planet 9. The orbits of some of the objects in the outer solar system are best explained by the presence of a large planet which affects their orbits.
If Planet 9 exists its closest approach to the sun is about 200AU. It would have an orbital period of between 10,000 and 20,000 years.
There are currently projects underway to try and find the planet by examining images of the area of the sky where it is predicted to be. This is done by displaying multiple images of the same area of sky taken at time intervals and looking for something which moves.