Plate tectonics on exoplanets/moon.

[KTevolved]

What would be the minimum mass for an exoplanet or moon to sustain plate tectonics? I would think its 0.2 Earth masses.

 

[willstaruss22]

Yes 0.2 Earth masses sounds right for the very minimal mass for sustained plate tetonics but you would need water to lubricate the plates. There are other factors that come into play also like rotation, tidal effects of a moon, how much heat the interior has. Even a small planet or moon could have enough heat in the interior.