Why didn't Jool become a hot Jupiter?

[Lo.M]

Why didn't Jool become a hot Jupiter? 

Spoiler

https://en.m.wikipedia.org/wiki/Hot_Jupiter

 

[wumpus]

Same reason that Jool still has 4 moons, that's the way the developers hard coded it.

From what I understand, the first corrected gravity simulation of Jool's moons ejected one moon in just a few orbits.  Also if Kerbin is significantly more dense than uranium, we can only wonder about Juul.  On the other hand, that density probably means that the atoms that make it up are pretty high on the periodic table and unlikely to fuse.  And as a "gas giant", less likely to be as dense as Kerbin (not bothering to run the numbers).

A better question is how much fission to expect from Kerbin.

[kerbiloid]

A hot Jool would not be green. 

So, they question is: why did they want exactly green?

[Jacke]

1 hour ago, Lo.M said:

Why didn't Jool become a hot Jupiter?

Because Jool, like Jupiter, didn't end up close to the star it orbits.   To get that large requires them to form out where they are now.  There's various models of planetary formation that predict where the original large planets forms and when they had major changes in semi-major axis.  But most movement say for the Solar System have Saturn, Uranus, and Neptune move the most.  Jupiter moves very little.  In the stock Kerbol system, Jool is the sole large planet, so there'd be little interaction to move Jool.  Biggest interaction would be with the accretion disk from which it formed.

[Gargamel]

Closed by OP request.