There is no moon in our solar system that has a thin oxygen atmosphere. While some moons, like Titan (Saturn's largest moon), have atmospheres, they are primarily composed of different gases like nitrogen and methane.

Here's why:

* Oxygen is reactive: Oxygen readily combines with other elements, making it difficult to exist in large quantities in a planetary or lunar atmosphere.

* Gravitational pull: Most moons have weak gravitational pulls, making it difficult to retain an atmosphere over long periods.

While some moons may have traces of oxygen in their atmospheres, it's not enough to be considered a thin oxygen atmosphere.