| A. Laurent|
2.208 AU (330.360 Gm)
22 January 1858
| January 22, 1858|
2.523 AU (377.381 Gm)
2.365 AU (353.871 Gm)
| 56 Melete, 18 Melpomene, 68 Leto, 20 Massalia, 47 Aglaja|51 Nemausa Wikipedia
51 Nemausa /nᵻˈmɔːzə/ 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.
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. It may have a water content of about 14%.
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. This is close to the present-day estimate of 147.9 km. Lightcurve data suggests that it may have a small moon. Nemausa has been studied by radar.