The Solar System's outermost edge could host an unknown planet

[Alfonso Maruccia]

In context: The Oort cloud is a cloud-like structure that scientists believe surrounds the Solar System, essentially behaving like the outermost limit of the Sun's gravitational influence in the Milky Way. The cloud-like structure is mainly composed of icy debris which replenishes the Solar System with its long-period comets, but it could also host a yet unknown, giant-like planet.

Speculationn about a hypothetical ninth planet (sorry Pluto) in the Solar System have long been focused on Planet X, but a recently published study proposes that an unknown, large planet could be hiding far beyond standard planetary orbits. This Uranus or Jupiter-like planet would orbit the Solar System – and not just the Sun – within the Oort cloud, meaning that it would dwell in the outermost limit of the Sun's gravitational pull.

According to the study, these theoretical Oort cloud (exo)planets could be a standard feature for one in every 200 - 3,000 stars, which is likely an overestimation as the researchers didn't account for instabilities taking place during the formation of a star and its planetary disk.

Scientists from the French National Centre for Scientific Research (CNRS) and other research institutions ran complex "N-body simulations" of dynamical instabilities to assess how a large planet could be cast out of a solar system, or how an already established planetary system could capture a runaway planet strolling through the galactic plane.

The estimated fraction of ejected planets that are trapped in the Oort clouds ranges from 1 to 10%, the study says, which is depending on the initial planetary mass distribution during the system's creation. If the Solar System's dynamical instability "happened after birth cluster dissolution," the study continues, there's a 7% chance that an ice giant could be captured in the Sun's Oort cloud.

Therefore, the unknown giant planet at the edge of the Solar System could likely be a wandering exo-planet that was captured by the Sun's gravitational influence after the formation of the Solar System.

The Oort cloud surrounds the Sun at distances ranging from 2,000 to 200,000 AU, or 0.03 to 3.2 light-years, which means that the aforementioned gravitational pull is pretty weak compared to what keeps the eight (confirmed) planets in the Solar System in place.

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https://www.techspot.com/news/99367-solar-system-outermost-edge-could-host-unknown-planet.html

 

[GreyOmega]

If it's in the Oort cloud and given the IAU definition of a planet requires clearing the neighborhood around it's orbit, would this actually still be allowed to be classified as a planet?

 

[Plutoisaplanet]

If it's in the Oort cloud and given the IAU definition of a planet requires clearing the neighborhood around it's orbit, would this actually still be allowed to be classified as a planet?

It wouldn't even be considered an orbit of the sun because the Oort Cloud is in interstellar space, so any references to "planets" are simply referring to the "size" and are being grabbed by news headlines for clickability (or lack of research). It should only be referred to as an exoplanet and in limited capacity compared to actual planets to prevent further confusion.

But to your point, a planet as big as Jupiter wouldn't be considered a planet given that massive orbital trajectory would never be cleared of its debris. I'd guess objects are likely to be flying in random trajectories through clouds likely that. Even the largest of the terrestrial planets (Earth) is ineligible to be a planet in Pluto's orbit. Therefore, if they ever discover any other planets, they would still be dwarf planets. Anything larger than Jupiter would end up as a star, which are far more easily detectible.

The funny thing is the problem with the definition of a planet is it's based on the least bad explanation, using data almost exclusively from our own solar system. Astronomers make the same mistake here by predicting their theory is expected in other solar systems (notice the wide range of it happening in 1/200-3000 systems) and assuming "Oort cloud planets" are even a standard solar system feature. It would be our best opportunity to study an exoplanet, but they should refer to them as existing in interstellar space and make a note of the 5000+ exoplanets already discovered like the ones detailed here: https://en.wikipedia.org/wiki/Lists_of_exoplanets

 

[kira setsu]

If it's in the Oort cloud and given the IAU definition of a planet requires clearing the neighborhood around it's orbit, would this actually still be allowed to be classified as a planet?

nope,

we just wanna find it so we can say its not a planet, if theres one thing humanity is good at its working hard as hell to find something to attack.

 

[aCupOfJuice]

nope,

we just wanna find it so we can say its not a planet, if theres one thing humanity is good at its working hard as hell to find something to attack.

No we're not. It's such stupidly common statement that humanity always attacks everything... When in reality we've been working hard as hell for the past millenia to decrease violence globally and doing REALLY good at this. So well yeah... I don't know why I wrote this, just hate when people say something like that about humanity

 

[p51d007]

PLUTO is still a planet in my book. <wink>

 

[Plutoisaplanet]

PLUTO is still a planet in my book. <wink>

Damn right it is

 

[Darkmatter]

Since there's so much debris in the Ort Cloud, I'm surprised that they can't find some of the larger rocks using wide field optical lenses and use computers to look for sudden and temporary occlusion of stars as these larger bodies fly in front of them. It would take quite a while, but I think it could be possible. Also, if this non-planet is that big, you'd think that instruments from space could possibly pick up slight changes in gravitational pull. Hell, we might even be able to use our own star. We use it to find planets in other systems partly based on it's wobble.

 

[mbrowne5061]

Therefore, if they ever discover any other planets, they would still be dwarf planets.

Honestly, that name - "dwarf planet" objectively sucks. It pre-supposes that any planet discovered in the outter solar system will always be "small".

Imo, call "everything" planets, and implement an objective classification system; "class 1" are your Earths and Jupiters; "class 2" are your Plutos; "class 3" are your wondering giants and particularly "large" and stable oort cloud objects. Or whatever actual astronomers think would be better delineations between classes. But the whole planet/planetoid/dwarf planet/wandering planet debate misses a lot of what the heart of the matter is: what kind of orbit an object exists in, not just its size or composition.

Anything larger than Jupiter would end up as a star, which are far more easily detectible.

I thought this was debunked a while ago? That you need to get ~much~ larger than Jupiter before you get to ignition? Much larger than Jupiter, and you do start to flirt with the requirements to become a brown dwarf, but there is more to it than just size, as well (good luck triggering fusion is the gas giant is made mostly of something like, say, Radon, no matter how large the planet gets)