The nearest approach is 0.988x Lunar Distance (379,868 km), 60 Earth radii out. The size is very roughly 6.7 meters, 22 feet. If it hit the atmosphere, the airburst would be about 5 kilotons. Airbursts like that happen every few years. https://en.wikipedia.org/wiki/Meteor_air_burst#After_1900
Is there some reason we would already know, or can these things just suddenly show up?