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According to

Space facts

The Asteroid Belt is located in an area of space between the orbits of Mars and Jupiter. That places it between 2.2 and 3.2 astronomical units (AU) from the Sun

But asteroids from the asteroid Velt like Pallas and Hygiea have an aphelion of 3.4119 AU and 3.5024 AU respectively. So my question is, which is the farthest distance a particular distant known-identified object from the asteroid belt can get from the sun?

Updated since the question might seem unclear. I'm asking for a currently known object from the asteroid belt which gets closer to Jupiter.

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  • $\begingroup$ Someone asked a similar question: what's the greatest distance from the Sun that an object could still be in the Sun's gravitational field and be orbiting the Sun (ie, the object's orbital ellipse remains within the area where the Sun's gravity is greater than that of any other star). I don't have an answer to either question, but you might look for this other question. $\endgroup$ – barrycarter Feb 19 '19 at 17:46
  • $\begingroup$ But I mean any known object between the orbits of Mars and Jupiter. Not a theoretical object (since I understand there are millions) $\endgroup$ – Pablo Feb 19 '19 at 17:48
  • $\begingroup$ Updated the title of the question $\endgroup$ – Pablo Feb 19 '19 at 17:53
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    $\begingroup$ By definition anything inside the orbit of Jupiter (and thus not directly orbiting Jupiter) is in the asteroid belt. I think your question is still incorrectly worded. Perhaps you mean "what's the most distant identified object in the asteroid belt" ? $\endgroup$ – Carl Witthoft Feb 19 '19 at 19:00
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tl;dr: The key part the question is the phrase

...from the asteroid belt...

There are lots of asteroids and only some of them are considered to be in "the asteroid belt" or to be main-belt asteroids. As @zephyr's answer to the question Do astronomers generally agree that the distinction between comets and astroids is not so clear? points out, even the definition of what is or isn't an asteroid is under debate and review. To the question of which is the farthest a main belt asteroid can get from the Sun, the answer depends on exactly how you draw your line.

There are also families and groups of asteroids, and while these have visually clear clumps and clusters when plotted in certain ways, they may not have absolute universally accepted definitions of who's in and who's out.

See this and this for some families within the main belt.


While the OP"s link says

The Asteroid Belt is located in an area of space between the orbits of Mars and Jupiter. That places it between 2.2 and 3.2 astronomical units (AU) from the Sun. The belt is about 1 AU thick.

that wording seems awkward since "between the orbits of between the orbits of Mars and Jupiter" only really puts it between 1.4 and 5.5 AU.

The first sentence of Wikipedia's Asteroid belt says:

The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter

repeat, "roughly" and it goes on to say

The asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids.

The article also includes the figure shown below, showing that there are plenty of other groups of asteroids besides those designated as "main belt". I am not sure if there is a 100% absolutely IAU-official definition that you can apply to any set of orbital parameters that will return Yes or No to the question "is this one main belt?" but in general it looks like asteroids with a semimajor axis beyond 3.3 AU, or a high eccentricity, or a high inclination would not be called "main belt" by most astronomers.

As @PM2Ring points out Kirkwood Gaps delineate statistical sub-groupings of the main belt.

A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids. They correspond to the locations of orbital resonances with Jupiter.

You can see that while there is a minimum around 3.3 AU due to the 2:1 resonance, there are "green" stragglers extending to the right that continue on past the arbitrary 3.5 AU edge of this plot of "main belt asteroids".

Kirkwood Gaps

Source

Kirkwood Gaps

Source

enter image description here

Screen shot from Scott Manley's video What Rock Star Brian May Discovered About Interplanetary Dust

which gives a better idea that there are groups and stragglers than the image in the OP's link:

enter image description here

Source

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    $\begingroup$ Annoyingly, Wikipedia doesn't fully explain the colours in that graph. Red is main belt, blue is others, but what are the grey ones around 5.2 AU? Also see the Kirkwood gap diagram. $\endgroup$ – PM 2Ring Feb 20 '19 at 0:48
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    $\begingroup$ On the first chart, Wikipedia doesn't describe them well, but the blues in the top chart would be the Alindas en.wikipedia.org/wiki/Alinda_asteroid and others (Green color I think), the Hecubas, followed by the Cybels, Hildas (4.0 AU 3:2 orbital ratio), Thules (4:3 orbital ratio, less common) and of course the Trojans. en.wikipedia.org/wiki/Hecuba-gap_asteroid Wikipedia's definitions aren't well written and they don't appear to offer a name for the orange. $\endgroup$ – userLTK Feb 20 '19 at 6:36
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    $\begingroup$ On the 2nd chart, the greys at 5.2 AU are the trojans. The 4.0 collection of blues are the Hildas. The blues above the reds that have main asteroid belt distances are distinguished by higher inclination, pushing them outside the main belt. As a sidebar, one of the odd things about the Kirkwood gaps is that the 3:2 ratio collects asteroids while the other higher ratios repel them. There was a question about that specifically, which I remember answering (kinda/sorta), but I can't find it now. $\endgroup$ – userLTK Feb 20 '19 at 6:49
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    $\begingroup$ @userLTK could it be this one? $\endgroup$ – uhoh Feb 20 '19 at 6:51
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    $\begingroup$ @uhoh Nice find. The 3 points of the Hilda triangle line up to L3, L4 and L5, so I think that explains the stability. Obviously asteroids don't orbit in a triangle, as that would be silly. $\endgroup$ – userLTK Feb 20 '19 at 7:11

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