Sariana21 posted...
Nothing in the scenario indicates that the
mass
of the moon changed, just the
size
.
It would be closer. Remember its halfway between the Lagrange point. If the mass stayed the same it would be larger tides and work the tectonics more. If the mass got larger it would tear both apart.
In my time in Elite Dangerous I saw plenty of systems like this. I distinctly remember 2 earth size planets orbiting each other. I brought it up to the forum at the time and explained the distance is within the Roche limit
https://en.m.wikipedia.org/wiki/Roche_limit