# Why isn't there a large gap in the number of captured moons Jupiter and Saturn have?

Given that Jupiter is roughly 3x as massive compared to Saturn and is located right next to the asteroid belt, it feels that Jupiter should easily have a larger amount of captured moons. However currently, due to a recent survey of Saturn discovering 20 new moons, Saturn has 57 observed captured moons compared to Jupiters 71.

Also summing the mass of the 6 largest captured moons for each planet gives:
- Jupiter: 7.844*10^18kg
- Saturn: 8.372*10^18kg

Why isn't there a larger gap between the number and mass of Jupiter and Saturns captured moons?

Note: While Jupiter has a very large amount of Trojan asteroids, the main focus of the question is moons directly in orbit around the main planet.

• Possible duplicate of astronomy.stackexchange.com/questions/13419/… Commented May 26, 2020 at 10:08
• It's unusual to see you leave a "possible duplicate" message under your own question. In Stack Exchange what makes it a duplicate is if answers there also answer your question. If you feel they sufficiently answer your question, then you can click "close" and start the process yourself. If you feel you need an answer that differs or goes beyond what's there, then you can mention what that might be in your question so that this doesn't get closed.
– uhoh
Commented May 26, 2020 at 10:53
• @uhoh I don't think it's a duplicate, but it felt like there was a lot enough in common between the two questions to argue closure. In this case, I wanted to get the ball rolling. However I've adjusted the focus of the question to specify Jupiter to the point where I think this is it's own question. Commented May 26, 2020 at 11:50
• The number of moons is not expected to be a fundamental physical parameter. More the total mass in the moons. And for the all moons-to-planet mass ratios, all giant planets have similar values, indicating a similar formation mechanism for the moons. Commented May 26, 2020 at 12:21
• @StephenG - The OP is rejecting objects captured at Jupiter's triangular libration points (L4 and L5), which are called pseudo moons by some, as moons. Commented May 26, 2020 at 21:17