1998 KY26

1998 KY26 is a nearly spherical sub-kilometer asteroid, classified as a near-Earth object of the Apollo group. It measures approximately 30 meters (100 feet) in diameter and is a fast rotator, having a rotational period of only 10.7 minutes. 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]

1998 KY26
Three views of a computer model of 1998 KY26, derived from radar observations in 1998
Discovery [1][2]
Discovered bySpacewatch
(Tom Gehrels)[3]
Discovery siteKitt Peak Obs.
Discovery date28 May 1998
(discovery: first observed only)
Designations
1998 KY26
NEO · Apollo [1][4]
Orbital characteristics [1]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc22.54 yr (8,231 days)
Aphelion1.4819 AU
Perihelion0.9840 AU
1.2329 AU
Eccentricity0.20192
1.37 yr (500.04 days)
359.504°
0° 43m 11.781s / day
Inclination1.4810°
84.366°
209.378°
Earth MOID0.002531 AU (0.985 LD)
Physical characteristics
Mean diameter
30 m (effective diameter)[5]
20–40 m (range)[1]
0.1782 h[6]
0.1784 h[5][7]
0.12[5]
0.124 (derived)[4]
X[4]
B–R=0.083±0.070[5]
V–R=0.058±0.055[5]
R–I=0.088±0.053[5]
25.5±0.3[1][4][5]

    On 10 December 2020 it was recovered by the Cerro Paranal and Mauna Kea observatories. The orbit is now well known with an uncertainty of 0, so it was possible to identify two more observations of 2002 by Mauna Kea Observatory.[8]

    Orbit and classification

    1998 KY26 orbits the Sun at a distance of 1.0–1.5 AU once every 16 months (500 days). Its orbit has an eccentricity of 0.20 and an inclination of 1° with respect to the ecliptic. It has an Earth minimum orbital intersection distance of approximately 0.0025 AU (374,000 km; 232,000 mi), corresponding to 0.98 lunar distances.[1]

    As a result, it is one of the most easily accessible objects in the Solar System,[9] and its orbit frequently brings it on a path very similar to the optimum Earth–Mars transfer orbit.[1] This, coupled with the fact that it is water-rich, makes it an attractive target for further study and a potential source of water for future missions to Mars.[10]

    Physical properties

    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.

    1998 KY26 is characterized as a potentially metallic X-type asteroid.[4] Optical and radar observations indicate that it is a water-rich object.[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.[5] As a result, it cannot possibly be a rubble pile, as many asteroids are thought to be, and must instead be a monolithic object.[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.

    Exploration

    In September 2020, a mission extension for JAXA's Hayabusa2 asteroid sample return probe was selected to do additional flybys of two near-Earth asteroids: (98943) 2001 CC21 in July 2026 and a rendezvous with 1998 KY26 in July 2031. The rendezvous with 1998 KY26 will be the first visit of a rapidly rotating micro-asteroid.[11] This will also make 1998 KY26 the smallest object to ever be studied by a spacecraft. [12]

    Further reading
    • Tholen, D. J. (September 2003). "Recovery of 1998 KY26: Implications for Detecting the Yarkovsky Effect (abstract only)". Bulletin of the American Astronomical Society. 35 (4). Archived from the original on 14 February 2012. Retrieved 25 April 2009.

    References
    1. "JPL Small-Body Database Browser: (1998 KY26)" (2020-12-12 last obs.). Jet Propulsion Laboratory. Retrieved 1 August 2017.
    2. "1998 KY26". Minor Planet Center. Retrieved 1 August 2017.
    3. "Spacewatch discovery of 1998 KY26". SPACEWATCH Project. 7 April 2004. Archived from the original on 1 July 2010. Retrieved 1 August 2017.
    4. "LCDB Data for (1998 KY26)". Asteroid Lightcurve Database (LCDB). Retrieved 1 August 2017.
    5. Ostro, Steven J.; Pravec, Petr; Benner, Lance A. M.; Hudson, R. Scott; Sarounová, Lenka; Hicks, Michael D.; et al. (June 1999). "Radar and Optical Observations of Asteroid 1998 KY26" (PDF). Science. 285 (5427): 557–559(SciHomepage). Bibcode:1999Sci...285..557O. doi:10.1126/science.285.5427.557. PMID 10417379.
    6. Hicks, M. D.; Weissman, P. R.; Rabinowitz, D. L.; Chamberlin, A. B.; Buratti, B. J.; Lee, C. O. (September 1998). "Close Encounters: Observations of the Earth-crossing Asteroids 1998 KY26 and 1998 ML14". American Astronomical Society. 30: 1029. Bibcode:1998DPS....30.1006H.
    7. Pravec, P.; Sarounova, L. (June 1998). "1998 KY26". IAU Circ. 6941 (6941): 2. Bibcode:1998IAUC.6941....2P.
    8. "MPEC 2020-X181 : 1998 KY26". Minor Planet Electronic Circular. Minor Planet Center. 15 December 2020. Retrieved 16 December 2020.
    9. "1998 KY26". Retrieved 25 April 2009.
    10. "Astronomy Picture of the Day: Asteroid 1998 KY26". NASA. 19 September 2002. Retrieved 1 August 2017.
    11. Gough, Evan (25 September 2020). "Hayabusa2's Mission isn't Over. It has a New Asteroid Target to Visit: 1998 KY26". Universe Today. Retrieved 1 October 2020.
    12. http://www.geocities.ws/zlipanov/selected_asteroids/1998ky26/1998ky26.html
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