Discovered by James Craig Watson Minor planet category Main belt Discovered 10 October 1874 Orbits Sun Discoverer James Craig Watson | Discovery date 10 October 1874 Observation arc 121.07 yr (44222 d) Inclination 10.9127° Spectral type C-type asteroid Asteroid group Asteroid belt | |
Aphelion 3.26884 AU (489.012 Gm) Perihelion 2.29261 AU (342.970 Gm) Similar 161 Athor, 128 Nemesis, 165 Loreley, 127 Johanna, 56 Melete | ||
Main belt asteroid 139 juewa
139 Juewa (/dʒuːˈeɪwɑː/ jew-AY-wah) is a very large and dark main belt asteroid. It is probably composed of primitive carbonaceous material. It was the first asteroid discovered from China.
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Juewa was discovered from Beijing by the visiting American astronomer James Craig Watson on 10 October 1874; Watson was in China to observe the transit of Venus. Watson asked Prince Gong to name the asteroid. Gong's choice was 瑞華星 (roughly, "Star of China’s Fortune"). Watson used only the first two characters, transliterating them as Juewa according to the conventions of his time (in modern pinyin, it would be transliterated as ruìhuá).
There have been three reported stellar occultations by Juewa, most recently on 26 September 2007.
13-cm radar observations of this asteroid from the Arecibo Observatory between 1980 and 1985 were used to produce a diameter estimate of 172 km. Based upon radar data, the near surface solid density of the asteroid is 1.5+0.5
−0.5 g cm−3.