In the Solar System, the object closest to Earth is the Moon, which is a natural satellite orbiting our planet.

In the Alpha Centauri system, the closest object to Alpha Centauri A and Alpha Centauri B is Proxima Centauri, a red dwarf star.

In the TRAPPIST-1 system, the closest object to the central star TRAPPIST-1 is TRAPPIST-1b, a terrestrial exoplanet.