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〕 |discoverer = Spacewatch, Tom Gehrels |discovered = 1998-05-28 |discovery_site = Arizona |mp_name = |mp_category = |alt_names = |orbit_ref = |epoch = 2455000.5 (2009-Jun-18.0) |aphelion = 1.4804157 ± 7.2381e-07 AU |perihelion = 0.98381275 ± 1.6462e-07 AU |semimajor = 1.23211426 ± 6.0241e-07 AU |eccentricity = 0.2015247 ± 4.9736e-07 |period = 1.37 ± 1.003e-06 yr (499.5453 ± 0.00036636 d) |avg_speed = |inclination = 1.481086 ± 9.0515e-06° |asc_node = 84.44936 ± 5.0927e-05° |mean_anomaly = 358.483 ± 0.002236° |arg_peri = 209.22902 ± 9.7658e-05° |satellites = |dimensions = |mass = |density = |surface_grav = |escape_velocity = |sidereal_day = 10.704 min |axial_tilt = |pole_ecliptic_lat = |pole_ecliptic_lon = |albedo = |temp_name1 = |mean_temp_1 = |max_temp_1 = |temp_name2 = |max_temp_2 = |spectral_type = |abs_magnitude = 25.456 }} (also written 1998 KY26) is a small near-Earth asteroid. It 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 in diameter. 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 accessible objects in the Solar System, and its orbit frequently brings it on a path very similar to the optimum Earth–Mars transfer orbit.〔 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. ==Physical properties== Asteroid 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 was found to be a fast rotator, several other small asteroids have been found to also have short rotation periods, some even faster than . Optical and radar observations indicate that is a water-rich object.〔 These physical properties were measured by 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「1998 KY26」の詳細全文を読む スポンサード リンク
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