6498 Ko, provisional designation 1992 UJ₄, is a stony Flora asteroid and exceptionally slow rotator from the inner regions of the asteroid belt, approximately 4 kilometers in diameter. The asteroid was discovered on 26 October 1992, by Japanese amateur astronomers Kin Endate and Kazuro Watanabe at Kitami Observatory on eastern Hokkaidō, Japan.^[5] It was named for Japanese scientist Ko Nagasawa.^[2]

Ko is a member of the Flora family, one of the largest groups of stony asteroids in the main-belt. It orbits the Sun in the inner main-belt at a distance of 1.9–2.7 AU once every 3 years and 5 months (1,258 days). Its orbit has an eccentricity of 0.17 and an inclination of 8° with respect to the ecliptic.^[1]

A first precovery was taken at Palomar Observatory in 1954, extending the asteroid's observation arc by 38 years prior to its discovery.^[5]

This minor planet was named in honor of Japanese scientist Ko Nagasawa (born 1932), who became a keen researcher of meteors and workes for the Public Information Office at the National Astronomical Observatory of Japan, after retiring from the Earthquake Research Institute, University of Tokyo in 1994.^[2]

At the Dodaira Station, after which the minor planet 14313 Dodaira is named, Ko has obtained numerous photographic spectra of the 1965-Leonid meteor shower. The minor planet's name was proposed by the second discoverer, Kazuro Watanabe, following a suggestion by Japanese astronomer Kōichirō Tomita.^[2] The approved naming citation was published by the Minor Planet Center on 20 June 1997 (M.P.C. 30099).^[6]