There has to be a sweet spot, i.e. speed, distance, mass for objects that pass close to Earth; for them to be captured by Earth's gravity for them to orbit. Are there any objects known to have done this and are they tracked?

Second question. Are there any known tracked objects at Earth's Orbit Trojan points? Or rumored objects? Maybe you know and can't talk about it. First heard speculation on this in the late 70's.

Inquiring minds want to know!