<p>As we know, Pluto is within the Kuiper belt, and it only makes up about $0.077\%$ times the mass of all of the object within its orbit. Now, in comparison, Earth has objects in its orbit, but it is $1.7$ million times the mass of all of the objects. </p>

<p>It's been debated in the past (by supporters of Pluto being a planet) that if Earth were in Pluto's place, it wouldn't be able to clear the neighborhood. So, with Pluto being even smaller than Earth's moon, it would have to gain a significant amount of mass to be able to clear its orbit. </p>

CC BY-SA 3.0
2015-07-27T01:23:51.503Z
2015-07-27T01:23:51.503Z
matryoshka
<p><a href="https://en.wikipedia.org/wiki/Clearing_the_neighbourhood">This Wikipedia page</a> does a decent job of describing the orbit-clearing criterion, based on the original paper by Stern &amp; Levison (2002), which can be found <a href="http://www.boulder.swri.edu/~hal/PDF/planet_def.pdf">here (PDF)</a>.</p>

<p>In order to have cleared its orbit over a period of billions of years, an object needs a "Stern-Levison parameter" $\Lambda$ which is $&gt; 1$; Pluto has $\Lambda \approx 3$-$4 \times 10^{-3}$. Since $\Lambda$ depends on the square of the object's mass (see the Wikipedia page, or Equation 4 of Stern &amp; Levison), Pluto would need to be about fifteen to twenty times its current mass in order to cross the threshold.</p>

CC BY-SA 3.0
2015-07-27T20:59:49.867Z
2015-07-27T20:59:49.867Z
Peter Erwin
<p>How much more massive would Pluto have to be to clear its neighborhood?</p>

CC BY-SA 4.0
2021-06-22T11:43:13.497Z
Related: https://astronomy.stackexchange.com/questions/44478/which-kbos-would-one-have-to-merge-in-order-to-have-more-than-half-the-kuiper-be
John
CC BY-SA 3.0
2015-07-26T22:54:58.020Z
Can you add a bit more detail and context to your question?
ProfRob
CC BY-SA 3.0
2015-07-27T01:56:19.817Z
Pluto and Neptune kind of cross orbits, so this is a tough one.     How big would it have to be to clear Neptune out of it's orbit, or, do we overlook that and let them both have clear orbits cause they're in resonance.
userLTK
<mass><pluto><trans-neptunian-object>
How much more massive would Pluto have to be to clear its neighborhood?
SpaceDrooler
# How much more massive would Pluto have to be to clear its neighborhood?

(Asked by: username_0 on 2015-07-26)

How much more massive would Pluto have to be to clear its neighborhood?

**Tags:** mass, pluto, trans-neptunian-object
> **Comments:**
> **username_2**: Can you add a bit more detail and context to your question?  
> **username_3**: Pluto and Neptune kind of cross orbits, so this is a tough one.     How big would it have to be to clear Neptune out of it's orbit, or, do we overlook that and let them both have clear orbits cause they're in resonance.  
> **username_1**: Related: https://astronomy.stackexchange.com/questions/44478/which-kbos-would-one-have-to-merge-in-order-to-have-more-than-half-the-kuiper-be  

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## 2 answers

### Answer by username_5 on 2015-07-27. Score: 7 | Accepted answer

[This Wikipedia page](https://en.wikipedia.org/wiki/Clearing_the_neighbourhood) does a decent job of describing the orbit-clearing criterion, based on the original paper by Stern & Levison (2002), which can be found [here (PDF)](http://www.boulder.swri.edu/~hal/PDF/planet_def.pdf).

In order to have cleared its orbit over a period of billions of years, an object needs a "Stern-Levison parameter" $\Lambda$ which is $> 1$; Pluto has $\Lambda \approx 3$-$4 \times 10^{-3}$. Since $\Lambda$ depends on the square of the object's mass (see the Wikipedia page, or Equation 4 of Stern & Levison), Pluto would need to be about fifteen to twenty times its current mass in order to cross the threshold.


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### Answer by username_4 on 2015-07-27. Score: 1

As we know, Pluto is within the Kuiper belt, and it only makes up about $0.077\%$ times the mass of all of the object within its orbit. Now, in comparison, Earth has objects in its orbit, but it is $1.7$ million times the mass of all of the objects.

It's been debated in the past (by supporters of Pluto being a planet) that if Earth were in Pluto's place, it wouldn't be able to clear the neighborhood. So, with Pluto being even smaller than Earth's moon, it would have to gain a significant amount of mass to be able to clear its orbit.


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