78 Diana is a large and dark main-belt asteroid. It was discovered by German astronomer Robert Luther on March 15, 1863,[6] and named after Diana, Roman goddess of the hunt. The asteroid is orbiting the Sun at a distance of 2.620 AU with a period of 4.24 years and an eccentricity (ovalness) of 0.207. The orbital plane is tilted at an angle of 8.688° relative to the plane of the ecliptic.[2] Its composition is carbonaceous and primitive.
 Orbital diagram | |
| Discovery | |
|---|---|
| Discovered by | Karl Theodor Robert Luther |
| Discovery date | March 15, 1863 |
| Designations | |
| (78) Diana | |
| Pronunciation | /daɪˈænə, daɪˈeɪnə/ dy-A(Y)N-ə[1] |
Named after | Diāna (Roman mythology) |
| Main belt | |
| Adjectives | Dianian (/daɪˈeɪniən/ dy-AY-nee-ən) |
| Orbital characteristics[2] | |
| Epoch December 31, 2006 (JD 2454100.5) | |
| Aphelion | 473.182 Gm (3.163 AU) |
| Perihelion | 310.686 Gm (2.077 AU) |
| 391.934 Gm (2.620 AU) | |
| Eccentricity | 0.207 |
| 1,548.922 d (4.24 yr) | |
Average orbital speed | 18.20 km/s |
| 353.808° | |
| Inclination | 8.688° |
| 333.582° | |
| 151.423° | |
| Physical characteristics | |
| Dimensions | 123.63±4.57 km[3] |
| Mass | (1.27±0.13)×1018 kg[3] |
Mean density | 1.28±0.19[3] g/cm3 |
| 7.2991[4] h | |
| 0.071 [5] | |
| C | |
| 8.09 | |
Photometric observations of this asteroid during 1986 and 2006–08 gave a light curve with a rotation period of 7.2991 hours and a brightness variation in the range 0.02–0.104 magnitude.[4] Based upon radar data, the near surface solid density of the asteroid is 2.7+0.8
−0.5 g cm−3.[7] 78 Diana occulted a star on September 4, 1980. A diameter of 116 km was measured, closely matching the value given by the IRAS satellite.
Diana is expected to pass about 0.003 AU (450,000 km; 280,000 mi) from (29075) 1950 DA on August 5, 2150.[8] Main-belt asteroid 4217 Engelhardt (~9 km in diameter) will pass about 0.0017 AU (250,000 km; 160,000 mi) from (29075) 1950 DA in 2736.[8]
References
edit- ^ "Diana". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
- ^ a b Yeomans, Donald K., "78 Diana", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 30 March 2013.
- ^ a b c Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
- ^ a b Radeva, V.; et al. (2011), "Rotation periods of the asteroids 55 Pandora, 78 Diana and 815 Coppelia", Bulgarian Astronomical Journal, vol. 17, pp. 133–141, Bibcode:2012MPBu...39...57P.
- ^ "Asteroid Data Sets". Archived from the original on 17 December 2009. Retrieved 13 January 2007.
- ^ "Numbered Minor Planets 1–5000", Discovery Circumstances, IAU Minor Planet center, retrieved 7 April 2013.
- ^ Magri, C.; et al. (December 2001), "Radar constraints on asteroid regolith compositions using 433 Eros as ground truth", Meteoritics & Planetary Science, vol. 36, no. 12, pp. 1697–1709, Bibcode:2001M&PS...36.1697M, doi:10.1111/j.1945-5100.2001.tb01857.x.
- ^ a b Giorgini, J. D.; Ostro, S. J.; Benner, L. A. M.; Chodas, P.W.; Chesley, S.R.; Hudson, R. S.; et al. (2002). "Asteroid 1950 DA's Encounter With Earth in 2880: Physical Limits of Collision Probability Prediction" (PDF). Science. 296 (5565): 132–136. Bibcode:2002Sci...296..132G. doi:10.1126/science.1068191. PMID 11935024. Archived from the original (PDF) on 4 July 2008.
External links
edit- 78 Diana at AstDyS-2, Asteroids—Dynamic Site
- 78 Diana at the JPL Small-Body Database
