2018 BD is a small asteroid and near-Earth object of the Apollo group, approximately 2–6 meters (7–20 ft) in diameter. It was first observed on 18 January 2018, by astronomers of the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, United States,^[1] just hours before passing about 0.10 lunar distances from the Earth.^[2]

2018 BD is an Apollo asteroid. It orbits the Sun at a distance of 0.75–1.36 AU once every 13 months (395 days; semi-major axis of 1.05 AU). Its orbit has an eccentricity of 0.29 and an inclination of 2° with respect to the ecliptic.^[2]

The object has an exceptionally low minimum orbital intersection distance with Earth of 900 km; 560 mi (0.000006019 AU), or 0.002 lunar distances.^[2]

Based on a generic magnitude-to-diameter conversion, 2018 BD measures between 2 and 6 meters in diameter, for an absolute magnitude of 30.154, and an assumed albedo between 0.05 and 0.20, which represent typical values for carbonaceous and a bright E-type asteroids, respectively.^[3] As of 2018, no rotational light curve of this object has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.^[2]

This minor planet has neither been numbered nor named.^[1]

• List of asteroid close approaches to Earth in 2018