It was first observed on 2 June 1998, by the Spacewatch survey at Kitt Peak National Observatory during 6 days during which it passed 800,000 kilometers (half a million miles) away from Earth (a little more than twice the Earth–Moon distance).

[2][3] The object's orbit is well known, since it was recovered in 2002 by the Hawaiian Observatory, and it was most recently observed, from 10 till 15 December 2020, by the Cerro Paranal.

[10] The physical properties of this object were measured by an international team of astronomers led by Dr. Steven J. Ostro of the Jet Propulsion Laboratory using a radar telescope in California and optical telescopes in the Czech Republic, Hawaii, Arizona and California.

[10] From light curve photometry in 1998, the object is measured to have a rotation period of only 10.7 minutes, which was considered to be one of the shortest sidereal days of any known Solar System object at the time; most asteroids with established rotational rates have periods measured in hours.

[6][5][7] It was the first such object to be discovered, but since 1998, several other small asteroids have been found to also have short rotation periods, some even faster than 1998 KY26.