| Discovery[1] | |
|---|---|
| Discovered by | K. Endate K. Watanabe |
| Discovery site | Kitami Obs. |
| Discovery date | 26 October 1992 |
| Designations | |
| (6498) Ko | |
Named after | Ko Nagasawa (Japanese scientist)[2] |
| 1992 UJ4 · 1964 PM 1971 QK3 · 1994 CD4 | |
| main-belt · Flora[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 62.24 yr (22,734 days) |
| Aphelion | 2.6660AU |
| Perihelion | 1.8955 AU |
| 2.2807 AU | |
| Eccentricity | 0.1689 |
| 3.44yr (1,258 days) | |
| 149.16° | |
| 0° 17m 9.96s / day | |
| Inclination | 7.9910° |
| 149.63° | |
| 156.73° | |
| Physical characteristics | |
| Dimensions | 3.99 km(calculated)[3] |
| 500h[a][b] | |
| 0.24(assumed)[3] | |
| S[3] | |
| 13.5[1] · 13.71[a] · 13.92±0.47[4] · 14.16[3] | |
6498 Ko, provisional designation1992 UJ4, is a stony Floraasteroid and exceptionallyslow rotator from the inner regions of theasteroid belt, approximately 4 kilometers in diameter. The asteroid was discovered on 26 October 1992, by Japanese amateur astronomersKin Endate andKazuro Watanabe atKitami Observatory on eastern Hokkaidō, Japan.[5] It was named for Japanese scientistKo Nagasawa.[2]
Ko is a member of theFlora family, one of the largest groups ofstony asteroids in the main-belt. It orbits the Sun in theinner main-belt at a distance of 1.9–2.7 AU once every 3 years and 5 months (1,258 days). Its orbit has aneccentricity of 0.17 and aninclination of 8° with respect to theecliptic.[1]
A firstprecovery was taken atPalomar Observatory in 1954, extending the asteroid'sobservation arc by 38 years prior to its discovery.[5]
AlthoughKo does not cross the orbit of any planet, it does make close approaches to other large asteroids, such as29 Amphitrite, which it approached within 0.038 AU in 1915. Further close approaches will take place in 2025 and 2135 at a distance of 0.012 and 0.009 AU, respectively. On 14 November 2009, the asteroid also made a close encounter with3 Juno at a distance of about 0.047 AU.[1]
A rotationallightcurve ofKo was obtained from photometric observations by Czech astronomerPetr Pravec at theOndřejov Observatory in June 2012. It rendered an exceptionally longrotation period of 500 hours with a brightness amplitude of 0.6 inmagnitude (U=2).[a][b]
TheCollaborative Asteroid Lightcurve Link assumes analbedo of 0.24, derived from the Flora family's largest member and namesake, the asteroid8 Flora, and calculates a diameter of 4.0 kilometers with anabsolute magnitude of 14.16.[3]
Thisminor planet was named in honor of Japanese scientist Ko Nagasawa (born 1932), who became a keen researcher ofmeteors and workes for the Public Information Office at theNational Astronomical Observatory of Japan, after retiring from theEarthquake Research Institute, University of Tokyo in 1994.[2]
At theDodaira Station, after which the minor planet14313 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 astronomerKōichirō Tomita.[2] The approved naming citation was published by theMinor Planet Center on 20 June 1997 (M.P.C. 30099).[6]
