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Three views of a computer model of asteroid 1998 KY26.
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Discovery[1]
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| Discovered by | Spacewatch, Tom Gehrels |
| Discovery site | Arizona |
| Discovery date | 1998-05-28 |
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Designations
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| Minor planet category |
Apollo |
| Epoch 2455000.5 (2009-Jun-18.0) |
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| Aphelion | 1.4804157 ± 7.2381e-07 AU |
| Perihelion | .98381275 ± 1.6462e-07 AU |
| Semi-major axis | 1.23211426 ± 6.0241e-07 AU |
| Eccentricity | .2015247 ± 4.9736e-07 |
| Orbital period | 499.5453 ± 0.00036636 d 1.37 ± 1.003e-06 yr |
| Mean anomaly | 358.483 ± 0.002236° |
| Inclination | 1.481086 ± 9.0515e-06° |
| Longitude of ascending node | 84.44936 ± 5.0927e-05° |
| Argument of perihelion | 209.22902 ± 9.7658e-05° |
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Physical characteristics
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| Dimensions | 30 metres (98 ft) |
| Sidereal rotation period |
10.704 min |
| Absolute magnitude (H) | 25.456 |
The asteroid 1998 KY26 (also written 1998 KY26) was discovered on June 2, 1998, by Spacewatch and observed until June 8, when it passed 800,000 kilometers (half a million miles) away from Earth (a little more than twice the Earth-Moon distance). It is roughly spherical and is only about 30 metres (98 ft) in diameter. Although it is nearly small enough be classified a meteoroid, the most common definition uses a diameter of 10 m as the demarcation, just making 1998 KY26 an asteroid.
With a rotation period of 10.7 minutes it has one of the shortest sidereal days of any known object in the solar system, and cannot possibly be a rubble pile. It is also one of the most easily accessed objects in the solar system,[3] and its orbit frequently brings it on a path very similar to the optimum Earth-Mars transfer orbit.[2] 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.[4]
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The discovery is attributed to an international team of astronomers led by Dr. Steven J. Ostro of the Jet Propulsion Laboratory. The team used a radar telescope in California and optical telescopes in the Czech Republic, Hawaii, Arizona and California.
Asteroid 1998 KY26 is the smallest solar system object ever studied in detail and, with a rotational period of 10.7 minutes, was the fastest-spinning object observed at the time of its discovery: most asteroids with established rotational rates have periods measured in hours. It was the first recognized minor object that spins so fast that it must be a monolithic object rather than a rubble pile, as many asteroids are thought to be. Since 1998 KY26 was found to be a fast rotator, several other small asteroids have been found to also have short rotation periods, some even faster than 1998 KY26.
Optical and radar observations indicate that 1998 KY26 is a water-rich object.[4]
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