<p>Let us consider this gas giant moon system:</p>
<p>Gas giant:</p>
<ul>
<li>7 Jupiter masses</li>
<li>1.37 Jupiter radii</li>
</ul>
<p>Moon 1</p>
<ul>
<li>0.317 earth masses</li>
<li>775332 km semi-major axis</li>
<li>40 hrs orbital period</li>
</ul>
<p>Moon 2</p>
<ul>
<li>0.2 earth masses</li>
<li>1015972 km semi-major axis</li>
<li>60 hrs orbital period</li>
</ul>
<p>Moon 3</p>
<ul>
<li>0.25 earth masses</li>
<li>1331300 km semi-major axis</li>
<li>90 hrs orbital period</li>
</ul>
<p>Moon 4</p>
<ul>
<li>0.2 earth masses</li>
<li>1744497 km semi-major axis</li>
<li>135 hrs orbital period</li>
</ul>
<p>Moon 5</p>
<ul>
<li>0.1 earth masses</li>
<li>2285938 km semi-major axis</li>
<li>202.5 hrs orbital period</li>
</ul>
<p>As you can see each moon is in a 2:3 orbital resonance with it's neighbor, which as far as I am aware should be one of the most stable. That being said I tried running this simulation in universe sandbox and the system loses stability rather quickly at a speed of 1 year per second. Given that I cannot dismiss it being an inaccuracy error caused by the speed, I'd like if you could help me shed some light on this.</p>
<p>Would this moon system remain stable in the long term? And in case it isn't would having all the moons in a laplace resonance be better?</p>

CC BY-SA 4.0
2024-09-05T13:57:00.990Z
The masses of the moons are quite significant so that their mutual interaction will play a role. Their surface acceleration is irrelevant for determining stability of the system. Their semi-major axis might be much more interesting (though it can be deduced from the planets and the moons' masses). Jupiter's main moons have a 1:2:4:~9 resonance.
planetmaker
CC BY-SA 4.0
2024-09-05T13:57:32.957Z
@planetmaker i'll add them
Juimy94
CC BY-SA 4.0
2024-09-05T14:05:03.143Z
If you want to dive into stability analysis a bit deeper, maybe you can start with https://www.sciencedirect.com/science/article/pii/S2211379721009785 and references therein... it's not trivial :)
planetmaker
<orbital-mechanics><distances><natural-satellites><gas-giants><orbital-resonance>
Stability of this complex gas giant moon system
Juimy94
# Stability of this complex gas giant moon system

(Asked by: username_0 on 2024-09-05)

Let us consider this gas giant moon system:

Gas giant:

* 7 Jupiter masses
* 1.37 Jupiter radii

Moon 1

* 0.317 earth masses
* 775332 km semi-major axis
* 40 hrs orbital period

Moon 2

* 0.2 earth masses
* 1015972 km semi-major axis
* 60 hrs orbital period

Moon 3

* 0.25 earth masses
* 1331300 km semi-major axis
* 90 hrs orbital period

Moon 4

* 0.2 earth masses
* 1744497 km semi-major axis
* 135 hrs orbital period

Moon 5

* 0.1 earth masses
* 2285938 km semi-major axis
* 202.5 hrs orbital period

As you can see each moon is in a 2:3 orbital resonance with it's neighbor, which as far as I am aware should be one of the most stable. That being said I tried running this simulation in universe sandbox and the system loses stability rather quickly at a speed of 1 year per second. Given that I cannot dismiss it being an inaccuracy error caused by the speed, I'd like if you could help me shed some light on this.

Would this moon system remain stable in the long term? And in case it isn't would having all the moons in a laplace resonance be better?

**Tags:** orbital-mechanics, distances, natural-satellites, gas-giants, orbital-resonance
> **Comments:**
> **username_1**: The masses of the moons are quite significant so that their mutual interaction will play a role. Their surface acceleration is irrelevant for determining stability of the system. Their semi-major axis might be much more interesting (though it can be deduced from the planets and the moons' masses). Jupiter's main moons have a 1:2:4:~9 resonance.  
> **username_0**: @planetmaker i'll add them  
> **username_1**: If you want to dive into stability analysis a bit deeper, maybe you can start with https://www.sciencedirect.com/science/article/pii/S2211379721009785 and references therein... it's not trivial :)  

---

## 0 answers

