Actually - it really doesn't matter where you log off because the game will place you in a safe spot once you log back in. Staying in the orbit path of some planet or even inside asteroid fields doesn't matter.
I actually tested this myself. I logged out inside asteroid fields tons of time when I was bountyhunting. I was always placed away from the actual rocks. Also - I logged numerous times right infront of the sun! When i logged back in - my ship was VERY far away.
And yes - once you log out, your ship is removed from the game instantly. Even if someone else comes to the exact same spot - you wouldn't be visible.