It doesn't necessarily have to increase the gravity...

by ZackDark , Not behind you. NO! Don't look., Thursday, August 29, 2013, 08:52 (4103 days ago) @ Jabberwok

Not really.

You see, with a smaller radius (assuming you are at the surface) the gravity would indeed be greater. Take black holes for one. They have pretty much the same mass it had when it was a dying star (not exactly the same, but definitely not 10 times more), yet it's only trouble when it's a black hole and not when it's a dying star. Why's that? Because it has a very much so reduced radius.

In mathematical terms, the gravitational pull outside of the body in question is a function of the mass/(distance from mass center^2), so the smaller the radius, the smaller the distance from the center of mass, the greater the pull.