Astronomy:139 Juewa

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Short description: Main-belt asteroid
139 Juewa
Discovery
Discovered byJames Craig Watson
Discovery date10 October 1874
Designations
(139) Juewa
Pronunciation/uˈwɑː/
Mandarin: [ɻuîxuǎ]
A874 TA
Minor planet categoryMain belt
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc121.07 yr (44222 d)
|{{{apsis}}}|helion}}3.26884 astronomical unit|AU (489.012 Gm)
|{{{apsis}}}|helion}}2.29261 AU (342.970 Gm)
2.78073 AU (415.991 Gm)
Eccentricity0.17553
Orbital period4.64 yr (1693.7 d)
Mean anomaly60.2817°
Mean motion0° 12m 45.187s / day
Inclination10.9127°
Longitude of ascending node1.83417°
165.566°
Physical characteristics
Dimensions156.60±2.8 km[1]
161.43±7.38 km[2]
Mass(5.54±2.20)×1018 kg[2]
Mean density2.51±1.05 g/cm3[2]
Equatorial surface gravity
0.0438 m/s²
Equatorial escape velocity
0.0828 km/s
Rotation period20.991 h (0.8746 d)
Geometric albedo0.0557±0.002[1]
0.0444±0.0164[3]
Physics~167 K
CP (Tholen)[3]
Absolute magnitude (H)7.78,[1] 7.924[3]


139 Juewa /uˈwɑː/ 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 the first two characters ('star' being redundant), transliterating them Juewa in Wade–Giles convention of the time. (In pinyin, 瑞華 is transliterated ruìhuá.)[4]

Multichord occultation by 139 Juewa, observed 31 August 2013 from N.S.W., Australia.
139 Juewa
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Since 1988 there have been 8 reported stellar occultations by Juewa. From the occultation on 31 August 2013 the best fit ellipse measures 148.3+/-4.3 km x 142.3 +/- 15.6 km.[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+0.5−0.5 g cm−3.[7]

References

  1. 1.0 1.1 1.2 1.3 Yeomans, Donald K., "139 Juewa", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=139, retrieved 12 May 2016. 
  2. 2.0 2.1 2.2 Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73: pp. 98–118, doi:10.1016/j.pss.2012.03.009, Bibcode2012P&SS...73...98C.  See Table 1.
  3. 3.0 3.1 3.2 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), Bibcode2012LPICo1667.6089P.  See Table 4.
  4. Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names. Springer Science & Business Media. p. 28. ISBN 978-3-540-00238-3. https://books.google.com/books?id=KWrB1jPCa8AC&pg=PA28. 
  5. "Asteroid Occultations" (in en). https://sbn.psi.edu/pds/resource/occ.html. 
  6. Ostro, S. J. et al. (August 1985), "Mainbelt asteroids - Dual-polarization radar observations", Science 229 (4712): pp. 442–446, doi:10.1126/science.229.4712.442, PMID 17738665, Bibcode1985Sci...229..442O. 
  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, doi:10.1111/j.1945-5100.2001.tb01857.x, Bibcode2001M&PS...36.1697M. 

External links