Astronomy:139 Juewa
| Discovery | |
|---|---|
| Discovered by | James Craig Watson |
| Discovery date | 10 October 1874 |
| Designations | |
| (139) Juewa | |
| Pronunciation | /dʒuˈeɪwɑː/ Mandarin: [ɻuîxuǎ] |
| A874 TA | |
| Minor planet category | Main belt |
| Orbital characteristics[1] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 121.07 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) | |
| Eccentricity | 0.17553 |
| Orbital period | 4.64 yr (1693.7 d) |
| Mean anomaly | 60.2817° |
| Mean motion | 0° 12m 45.187s / day |
| Inclination | 10.9127° |
| Longitude of ascending node | 1.83417° |
| 165.566° | |
| Physical characteristics | |
| Dimensions | 156.60±2.8 km[1] 161.43±7.38 km[2] |
| Mass | (5.54±2.20)×1018 kg[2] |
| Mean density | 2.51±1.05 g/cm3[2] |
Equatorial surface gravity | 0.0438 m/s² |
Equatorial escape velocity | 0.0828 km/s |
| Rotation period | 20.991 h (0.8746 d) |
| Geometric albedo | 0.0557±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 /dʒuˈeɪwɑː/ 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]
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| 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
- ↑ 1.0 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.
- ↑ 2.0 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, Bibcode: 2012P&SS...73...98C. See Table 1.
- ↑ 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), Bibcode: 2012LPICo1667.6089P. See Table 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.
- ↑ "Asteroid Occultations" (in en). https://sbn.psi.edu/pds/resource/occ.html.
- ↑ 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, Bibcode: 1985Sci...229..442O.
- ↑ 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, Bibcode: 2001M&PS...36.1697M.
External links
- 139 Juewa at AstDyS-2, Asteroids—Dynamic Site
- 139 Juewa at the JPL Small-Body Database
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