Did we miss something?..

[deathtical]

Either I've never asked this before or it has never come up (for me anyway). Ok, when you see a diagram of the solar system you see all the planets (and now dwarf planets) orbiting the sun in their nice elliptical orbits. Now these orbits are represented as being on the same "plane" as if they are all floating on the top of a pool. Now I have seen some that show the orbits to not be at the same "height" in space, some a little higher and some a little lower, but about the same for the most part. Now to my question. Have/do astronomers look for planets in our solar system that do/might not orbit along this plane? The reason I ask is because all the outer objects we've found in the kuiper belt seem to also be on this plane. Also, I am aware that some comets and asteroids orbit at various angles to the sun than the main body of planets. So why wouldn't/couldn't a planet? Hope my question makes sense. Thanks.

[Argos]

Yes, they do look in every possible direction. (*) Any other orbital plane would have to cross the ecliptic at times.

And welcome.

[loglo]

I think in practice most astronomers do not look very high above or below the ecliptic when performing searches for new solar system objects. This is because most of the objects in the solar system formed within the proto-planetary disk which formed during the collapse of the gas cloud that made the Sun. Space is big, telescope time is precious. Why search mostly empty space?

Having said that a lot of astronomy is not solar system based so there is still a possibility of finding objects off the ecliptic by chance.

[dtilque]

There are a number of solar system objects which are not especially near the ecliptic. Eris at 44° and Pallas at 34° are the two most prominent cases. There's a family of much smaller asteroids associated with Pallas which have inclinations between 30° and 38°. They are likely ejecta from craters on Pallas.

Other largish objects with fairly large inclinations are Makemake (29°), Haumea (28°), Orcus (20°), Ixion (19°), Pluto (17°) and Varuna (17°). There's a fair number of smaller objects with similar inclinations out there as well.

As far as astronomers looking at such high inclinations, Eris was in fact discovered by an astronomer looking for such objects at that inclination. Due to its distance, it was unlikely to be discovered by accident, since it moves so slowly that it wouldn't make a trail on a typical astronomical image, even one of several hours exposure.

ETA: After a bit more investigating, I found that there are two TNOs with extreme inclinations: 2008 KV₄₂ (104° or 76° retrograde) and 2002 XU₉₃ (77°). Current thinking is that these objects originated in the Oort Cloud rather than in the Kuiper Belt where they are now.

[deathtical]

Interesting...