139 Juewa

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139 Juewa
Discovered by James Craig Watson
Discovery date October 10, 1874
Main belt
Orbital characteristics[1]
Epoch December 31, 2006 (JD 2454100.5)
Aphelion 488.346 Gm (3.264 AU)
Perihelion 344.626 Gm (2.304 AU)
416.486 Gm (2.784 AU)
Eccentricity 0.173
1696.721 d (4.65 a)
17.72 km/s
Inclination 10.902°
Physical characteristics
Dimensions 161.43±7.38 km[2]
Mass (5.54±2.20)×1018 kg[2]
Mean density
2.51±1.05 g/cm3[2]
0.0438 m/s²
0.0828 km/s
Albedo 0.0444±0.0164[3]
Temperature ~167 K
Spectral type
CP (Tholen)[3]

139 Juewa (/ˈwɑː/ 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.

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).[4]

There have been three reported stellar occultations by Juewa, most recently on 26 September 2007.[5]

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.[6] Based upon radar data, the near surface solid density of the asteroid is 1.5+0.5
g cm−3.[7]


  1. ^ Yeomans, Donald K., "139 Juewa", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-03-30. 
  2. ^ a b c Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009.  See Table 1.
  3. ^ a b c Pravec, P.; et al. (May 2012), "Absolute Magnitudes of Asteroids and a Revision of Asteroid Albedo Estimates from WISE Thermal Observations", Asteroids, Comets, Meteors 2012, Proceedings of the conference held May 16–20, 2012 in Niigata, Japan (1667), Bibcode:2012LPICo1667.6089P.  See Table 4.
  4. ^ Lutz D. Schmadel, Dictionary of Minor Planet Names, p. 28.
  5. ^ "OCCULTATION OF UCAC2 17551271 BY 139 JUEWA". Retrieved 22 November 2012. 
  6. ^ Ostro, S. J.; et al. (August 1985), "Mainbelt asteroids - Dual-polarization radar observations", Science 229 (4712), pp. 442–446, Bibcode:1985Sci...229..442O, doi:10.1126/science.229.4712.442, PMID 17738665. 
  7. ^ Magri, C.; et al. (December 2001), "Radar constraints on asteroid regolith compositions using 433 Eros as ground truth", Meteoritics & Planetary Science 36 (12), pp. 1697–1709, Bibcode:2001M&PS...36.1697M, doi:10.1111/j.1945-5100.2001.tb01857.x. 

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