78 Diana

From Wikipedia, the free encyclopedia
78 Diana
Discovery
Discovered by Karl Theodor Robert Luther
Discovery date March 15, 1863
Designations
Named after Diana
Minor planet category Main belt
Orbital characteristics[1]
Epoch December 31, 2006 (JD 2454100.5)
Aphelion 473.182 Gm (3.163 AU)
Perihelion 310.686 Gm (2.077 AU)
Semi-major axis 391.934 Gm (2.620 AU)
Eccentricity 0.207
Orbital period 1548.922 d (4.24 a)
Average orbital speed 18.20 km/s
Mean anomaly 353.808°
Inclination 8.688°
Longitude of ascending node 333.582°
Argument of perihelion 151.423°
Physical characteristics
Dimensions 123.63 ± 4.57[2] km
Mass (1.27 ± 0.13) × 1018[2] kg
Mean density 1.28 ± 0.19[2] g/cm3
Equatorial surface gravity 0.0337 m/s²
Escape velocity 0.0638 km/s
Rotation period 7.2991[3] h
Albedo 0.071 [4]
Temperature ~172 K
Spectral type C
Absolute magnitude (H) 8.09

    78 Diana (dye-an'-a) is a large and dark main-belt asteroid. Its composition is carbonaceous and primitive. It was discovered by Robert Luther on March 15, 1863,[5] and named after Diana, Roman goddess of the hunt. 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.

    Photometric observations of this asteroid during 1986 and 2006–08 gave a light curve with a period of 7.2991 hours and a brightness variation in the range 0.02–0.104 magnitude.[3] Based upon radar data, the near surface solid density of the asteroid is 2.7+0.8
    0.5
    g cm–3.[6]

    Diana is expected to pass about 0.003 AU (450,000 km; 280,000 mi) from (29075) 1950 DA on August 5, 2150.[7] 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.[7]

    References

    1. Yeomans, Donald K., "78 Diana", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-03-30. 
    2. 2.0 2.1 2.2 Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73: 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009.  See Table 1.
    3. 3.0 3.1 Radeva, V. et al. (2011), "Rotation periods of the asteroids 55 Pandora, 78 Diana and 815 Coppelia", Bulgarian Astronomical Journal 17: 133–141, Bibcode:2012MPBu...39...57P. 
    4. Asteroid Data Sets
    5. "Numbered Minor Planets 1–5000", Discovery Circumstances (IAU Minor Planet center), retrieved 2013-04-07. 
    6. Magri, C. et al. (December 2001), "Radar constraints on asteroid regolith compositions using 433 Eros as ground truth", Meteoritics & Planetary Science 36 (12): 1697–1709, Bibcode:2001M&PS...36.1697M, doi:10.1111/j.1945-5100.2001.tb01857.x. 
    7. 7.0 7.1 Giorgini, J. D.; Ostro, S. J; Benner, L. A. M.; Chodas, P.W.; Chesley, S.R.; Hudson, R. S.; Nolan, M. C.; Klemola, A. R.; Standish, E. M.; Jurgens, R. F.; Rose, R.; Chamberlin, A. B.; Yeomans, D. K.; Margot, J.-L. (2002). "Asteroid 1950 DA's Encounter With Earth in 2880: Physical Limits of Collision Probability Prediction". Science 296 (5565): 132–136. Bibcode:2002Sci...296..132G. doi:10.1126/science.1068191. PMID 11935024. 


    This article is issued from Wikipedia. The text is available under the Creative Commons Attribution/Share Alike; additional terms may apply for the media files.