What if it's a planet temporarily captured by our solar system which is currently deataching due to an unstable orbit? Moons are temporary, why not planets, even suns.
Orbits don't just detach. Even at the predicted aphelion distance of 460 AU, P9 would have an orbital velocity of 1.4 km/s and a solar escape velocity of 2 km/s. So to detach from solar orbit you would need a minimum delta-v of 600 m/s. 600 m/s on a planet size object is only going to happen if a star happens to wander through the solar system.
It's possibly a transient object - ie not in orbit around the sun, but just passing through.
For all we know it formed billions of years ago in another system, and then was ejected from its home system from some near miss with its sister gas giant.
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What if it's a planet temporarily captured by our solar system which is currently deataching due to an unstable orbit? Moons are temporary, why not planets, even suns.
Orbits don't just detach. Even at the predicted aphelion distance of 460 AU, P9 would have an orbital velocity of 1.4 km/s and a solar escape velocity of 2 km/s. So to detach from solar orbit you would need a minimum delta-v of 600 m/s. 600 m/s on a planet size object is only going to happen if a star happens to wander through the solar system.
It's possibly a transient object - ie not in orbit around the sun, but just passing through.
For all we know it formed billions of years ago in another system, and then was ejected from its home system from some near miss with its sister gas giant.
My understanding was that it had to be in orbit for a long time to cause the observed pattern, but you could be right.