6498 Ko

6498 Ko
Discovery [1]
Discovered by K. Endate
K. Watanabe
Discovery site Kitami Observatory
Discovery date 26 October 1992
Designations
MPC designation 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 27 June 2015 (JD 2457200.5)
Uncertainty parameter 0
Observation arc 60.71 yr (22,175 days)
Aphelion 2.6653 AU
Perihelion 1.8963 AU
2.2808 AU
Eccentricity 0.1685
3.44 yr (1,258 days)
280.22°
Inclination 7.9910°
149.63°
156.78°
Physical characteristics
Dimensions 3.99 km (calculated)[3]
500 h[lower-alpha 1]
0.24 (assumed)[3]
S [3]
13.5[1]
13.71[lower-alpha 1]

    6498 Ko, provisional designation 1992 UJ4, is a stony asteroid and extremely slow rotator from the inner regions of the asteroid belt, about 4 kilometers in diameter. It was discovered on 26 October 1992, by Japanese amateur astronomers Kin Endate and Kazuro Watanabe at Kitami Observatory in eastern Hokkaidō, Japan.[4]

    The S-type asteroid is a member of the Flora family, one of the largest groups of stony asteroids in the main-belt. It orbits the Sun at a distance of 1.9–2.7 AU once every 3 years and 5 months (1,258 days). Its orbit shows an eccentricity of 0.17 and an inclination of 8 degrees from the plane of the ecliptic.[1]

    Although the asteroid does not cross the orbit of any planet, it does make close approaches to other large asteroids, such as 29 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 with 3 Juno at a distance of about 0.047 AU.[1]

    A photometric light-curve analysis by Czech astronomer Petr Pravec at the Ondřejov Observatory in 2012, rendered an exceptionally long rotation period of 500 hours with a brightness amplitude of 0.6 in magnitude.[lower-alpha 1] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24, a typical value for asteroids with a stony surface composition, and identical to the albedo of the Flora family's namesake, the asteroid 8 Flora.[3]

    The minor planet was named in honor of Japanese scientist Ko Nagasawa (b. 1932). After retiring from the Earthquake Research Institute, University of Tokyo in 1994, he worked for the Public Information Office at the National Astronomical Observatory of Japan. Nagasawa has long been interested in the study of meteors, and he obtained many high-quality photographic spectra of the 1965-Leonid meteor shower at the Dodaira Station, after which the minor planet 14313 Dodaira is named. The name was proposed by the second discoverer, Kazuro Watanabe, following a suggestion by Japanese astronomer Kōichirō Tomita.[2]

    References

    1. 1 2 3 Pravec (2012): rotation period of 500 hours with a brightness amplitude of 0.6 magnitude. CALL assigned a quality-code Q of 2 to the measurement, which means, that the result is based on less than full coverage, and that the period may be wrong by 30 percent or so. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (6498) Ko
    1. 1 2 3 4 5 "JPL Small-Body Database Browser: 6498 Ko (1992 UJ4)" (2015-08-07 last obs.). Jet Propulsion Laboratory. Retrieved January 2016.
    2. 1 2 Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (6498) Ko. Springer Berlin Heidelberg. p. 598. ISBN 978-3-540-00238-3. Retrieved January 2016.
    3. 1 2 3 4 5 "LCDB Data for (6498) Ko". Asteroid Lightcurve Database (LCDB). Retrieved January 2016.
    4. ↑ "6498 Ko (1992 UJ4)". Minor Planet Center. Retrieved January 2016.

    External links


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