51 Nemausa

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51 Nemausa
Discovered by A. Laurent
Discovery site Nîmes
Discovery date January 22, 1858
Named after
Main belt
Orbital characteristics
Epoch December 31, 2006 (JD 2454100.5)
Aphelion 2.523 AU (377.381 Gm)
Perihelion 2.208 AU (330.360 Gm)
2.365 AU (353.871 Gm)
Eccentricity 0.066
3.64 a (1328.853 d)
19.34 km/s
Inclination 9.972°
Physical characteristics
Dimensions 147.9 km[1]
(170×136) km[2]
Mass (2.48 ± 0.86) × 1018[3] kg
Mean density
1.43 ± 0.50[3] g/cm3
0.0413 m/s²
0.0782 km/s
Albedo 0.093[4]
Temperature ~181 K
Spectral type

51 Nemausa /nɨˈmɔːzə/ is a large asteroid-belt asteroid that was discovered on January 22, 1858 by one "A. Laurent", an obscure figure about whom little is known. Laurent made the discovery from the private observatory of Benjamin Valz in Nîmes, France. The house, at 32 rue Nationale in Nîmes, has a plaque commemorating the discovery. With Laurent's permission, Valz named the asteroid after the Celtic god Nemausus, the patron god of Nîmes during Roman times.[5]

Based upon its spectrum, this is listed as a C-type asteroid in the Tholen classification taxonomy, and as a Cgh by Bus and Binzel (2002). This indicates a composition similar to carbonaceous chondrite meteorites. Absorption features in the spectrum indicate the presence of phyllosilicates.[6] It may have a water content of about 14%.[7]

On August 17, 1979, the star SAO 144417 was occulted by 51 Nemausa. Photometric observation of this event from the Gissar and Alma-Ata observatories produced two chords, which were used to estimate a diameter of 150 km for the asteroid.[8] This is close to the present-day estimate of 147.9 km.[1] Lightcurve data suggests that it may have a small moon.[9] Nemausa has been studied by radar.[10]

See also[edit]


  1. ^ a b "JPL Small-Body Database Browser: 51 Nemausa" (2008-05-09 last obs). Retrieved 2008-05-23. 
  2. ^ "Diameters". Astronomical Applications Department of the U.S. Naval Observatory. Retrieved 2008-05-23. 
  3. ^ a b 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.
  4. ^ Asteroid Data Sets
  5. ^ Lutz D. Schmadel, Dictionary of Minor Planet Names, p.20.
  6. ^ Reynolds, C. M.; et al. (March 2009), "Compositional Study of 51 Nemausa: A Possible Carbonaceous Chondrite-like Asteroid", 40th Lunar and Planetary Science Conference, (Lunar and Planetary Science XL), held March 23–27, 2009 in The Woodlands, Texas 73, Bibcode:2009LPI....40.1285R. 
  7. ^ A. S. Rivkin (2002). "CALCULATED WATER CONCENTRATIONS ON C CLASS ASTEROIDS" (PDF). Lunar and Planetary Institute. Retrieved 2008-05-22. 
  8. ^ Kristensen, L. K. (June 1981), "The Size of 51 Nemausa", Astronomy and Astrophysics Supplement 44: 375–377, Bibcode:1981A&AS...44..375K. 
  9. ^ Other reports of asteroid/TNO companions
  10. ^ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. Retrieved 2011-10-30. 

External links[edit]