400405

400405 is a numbered minor planet belonging to the asteroid belt between Mars and Jupiter. It was assigned its permanent designation after its orbit was confirmed in the early 2010s. The object has not yet received an official name and is therefore usually referred to by its numerical identifier.

The asteroid was first observed on 12 September 2005 by the Lincoln Near‑Earth Asteroid Research (LINEAR) survey at the Socorro site in New Mexico, United States. Initial observations yielded a provisional designation of 2005 KG15. Subsequent follow‑up by the Catalina Sky Survey and the Mount Lemmon Survey helped to refine its orbital elements. The observations were sufficient for the Minor Planet Center to assign the permanent number 400405 in 2014.

Orbital calculations show that 400405 follows a typical main‑belt trajectory with a semi‑major axis of about 2.3 astronomical units. Its orbit has an eccentricity of 0.13 and an inclination of 8.5 degrees relative to the ecliptic. The asteroid completes one orbit around the Sun in roughly 3.5 Earth years and is classified as belonging to the inner part of the main belt, lying near the Eunomia dynamical family.

Physical characteristics inferred from photometric data suggest a relatively common S‑type composition, implying a moderately bright surface with an albedo near 0.20. Size estimates based on its absolute magnitude place its diameter at roughly 1.5 kilometres, assuming a typical spectral reflectivity. No rotational period has been published, and the asteroid has no known satellites. All information on 400405 is catalogued in the Minor Planet Center database, where astronomers can access its updated orbital and physical parameters.