Being that size can be really fucking intimidating to others.

I mean, it has a magnetic field 6 or 7 orders of magnitude higher than ours. Id guess that extra strength allows it to pull particles from much further away and possibly from sources much more reticent to give up their particles than solar wind

Im guessing it only occurs when it is in a cloud or trail of charged particles. or perhaps there is a local (climatic?) cycle that sends charged particles to the poles.

The Wikipedia linked in these comments says it is likely from electron precipitation. Basically the magnetic field traps free elections and thus "wiggles" as they interact with the field. This can make a (pulsed) radio jet shooting from the pole, which is how this planet was observed. These electrons can fine from atmospheric phenomena such as lightning or large storms.

Earth has the same but much weaker phenomenon, the Van Allen belt, which was a difficult challenge to handle in the early days of space exploration.

Kind of, but not really.

Auroras dont necessarily need a stars radiation. Any old radiation will do, so long as there are charged particles floating around. Jupiter, for example, has gigantic continuous aurora around the magnetic poles. If auroras only came from the sun, and the earth is much closer to the sun than Jupiter, wouldn't earth have a bigger aurora than Jupiter?

No, obviously. The size of the aurora depends on the size of the magnetic field interacting with charged particles and the number of those charged particles.

In the case of supermassive planets like Jupiter and this rogue planet, they produce way more of their own radiation than they recieve from the sun or space. This rogue "planet" in particular is so massive that it could actually fuse deuterium down in the core just with the pressures and temperatures of gravity crushing all that matter down. If you pumped enough hydrogen in there to quadruple the mass, it would probably ignite into a star quite comparable to our sun.

For that reason, it's better to think of this as more of a baby star that didn't quite eat enough wheaties than a planet in the traditional sense we think of here in our solar system.

With the crazy physics that come with suns and near dwarfs with similar mass, it's no surprise that it generates a titanic magnetic field, and as a bonus, it produces its own radiation. It creates all the necessary ingredients it needs to make it's own spectacular auroras with no actual outside interaction.

Tl;dr it makes it's own aurora

I hate that I laughed at that

Planets Gone Wild

This planet isn't in our solar system. We've found 6,053 exoplanets already, so it's a safe bet that there's lots more of them than you're aware of

https://en.wikipedia.org/wiki/Exoplanet

We have discovered over 6000 exoplanets in total, and over 100 in this year. I'd be surprised if you knew of all of them

Galaxy, not Solar System. There are a lot of planets in our galaxy that you’ve probably never heard of

Yep

Even with this mass this planet would have to pass one of the outer planets extremely close and quite slowly to have a chance of dragging a planet out of the solar system.

This is the same sort of idea as when galaxies merge. There is little chance of our solar system being effected in that scenario. There is just too much space to space.

That's one of my very favorite books. It's fantastic at setting the mood. The further books are ok but not as much to my taste.

You mean OnlyPlanets

Let's not. I like the solar systems orbits exactly as they are

Because the planet produces its own radiation. That much mass means this is less a "planet" and more of a proto star. It's actually large enough to fuse deuterium if the right conditions arise. Pour enough hydrogen in there to raise the mass three of four times what it has now and it'd be comparable to our sun.

Looks like a brown dwarf, especially from the Wiki page

No it is indeed an artists impression of the planet - it's on the wiki page.

I'm assuming that aurora only needs solar wind to happen on earth - or that solar wind outside the heliosphere is strong enough you don't need a star for it to happen.

In 2018 astronomers said "Detecting SIMP J01365663+0933473 with the VLA through its auroral radio emission, also means that we may have a new way of detecting exoplanets, including the elusive rogue ones not orbiting a parent star ...