51 Nemausa

Nemausa (minor planet designation: 51 Nemausa) is a large asteroid-belt asteroid that was discovered on January 22, 1858, by Joseph Jean Pierre Laurent. 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.[6]

51 Nemausa
Three-dimensional model of 51 Nemausa created based on light-curve
Discovery
Discovered byJ. Laurent
Discovery siteNîmes
Discovery dateJanuary 22, 1858
Designations
(51) Nemausa
Pronunciation/nɛˈmɔːsə/[1]
Named after
Nemausus
Main belt
AdjectivesNemausian /nɛˈmɔːsiən/
Orbital characteristics
Epoch December 31, 2006 (JD 2454100.5)
Aphelion2.523 AU (377.381 Gm)
Perihelion2.208 AU (330.360 Gm)
2.365 AU (353.871 Gm)
Eccentricity0.066
3.64 a (1328.853 d)
316.668°
Inclination9.972°
176.168°
2.820°
Physical characteristics
Dimensions147.9 km[2]
(170×136) km[3]
Mass(2.48±0.86)×1018 kg[4]
Mean density
1.43 ± 0.50[4] g/cm3
0.093[5]
G
7.35

    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.[7] It may have a water content of about 14%.[8]

    The first stellar occultation was observed on August 17, 1979, from the Gissar and Alma-Ata observatories produced two chords which were used to estimate a diameter of 150 km for the asteroid.[9] This is close to the present-day estimate of 147.9 km. Since then 51 Nemausa has been observed 20 times[10] in stellar occultation.

    Light curve inversion model DAMIT 1065 is a good match to a seven-chord occultation observed on 3rd September 2016, from which an equivalent Volume mean diameter of 146.4km, and an equivalent Surface mean diameter of 150.3 km was obtained.

    Lightcurve data suggests that it may have a small moon.[11] Nemausa has been studied by radar.[12]

    Images related to 51 Nemausa
    • A light-curve Inversion model (DAMIT 1065) and a seven-chord occultation of 51 Nemausa
    • Chart dated 22 January 1858
    • Detail of handwritten legend at top ("J. Laurent")

    See also

    References
    1. John Craig (1869) The Universal English Dictionary
    2. "JPL Small-Body Database Browser: 51 Nemausa" (2008-05-09 last obs). Retrieved 23 May 2008.
    3. "Diameters". Astronomical Applications Department of the U.S. Naval Observatory. Archived from the original on 27 September 2011. Retrieved 23 May 2008.
    4. Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
    5. Asteroid Data Sets Archived 2009-12-17 at the Wayback Machine
    6. Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names. Springer Science & Business Media. p. 20. ISBN 978-3-540-00238-3.
    7. 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.
    8. A. S. Rivkin (2002). "CALCULATED WATER CONCENTRATIONS ON C CLASS ASTEROIDS" (PDF). Lunar and Planetary Institute. Retrieved 22 May 2008.
    10. "Asteroid Data Sets". sbn.psi.edu. Retrieved 27 May 2018.
    11. Other reports of asteroid/TNO companions
    12. "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. Retrieved 30 October 2011.

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