858 El Djezaïr

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For the Algerian city, see Algiers.
858 El Djezaïr
Discovery [1]
Discovered by F. Sy
Discovery site Algiers Observatory
Discovery date 26 May 1916
MPC designation (858) El Djezaïr
Named after
Algiers (Arabic name)[2]
1916 a · A908 UC
A911 HE
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 106.80 yr (39010 days)
Aphelion 3.0983 AU (463.50 Gm)
Perihelion 2.5252 AU (377.76 Gm)
2.8118 AU (420.64 Gm)
Eccentricity 0.10192
4.71 yr (1722.1 d)
0° 12m 32.544s / day
Inclination 8.8726°
Earth MOID 1.51148 AU (226.114 Gm)
Jupiter MOID 1.9171 AU (286.79 Gm)
Jupiter Tisserand parameter 3.296
Physical characteristics
Mean radius
11.755±1.3 km
22.31 h (0.930 d)
Tholen = S

858 El Djezaïr, provisional designation 1916 a, is a stony asteroid from the asteroid belt, about 24 kilometers in diameter. It was discovered on May 26, 1916 by French astronomer Frédéric Sy at the Algiers Observatory in Algeria, North Africa.[1]

The asteroid orbits the Sun at a distance of 2.5–3.1 AU once every 4.71 years (1,722 days). The bright S-type asteroid has a very high geometric albedo of 0.32. Its rotation period has been measured to take 22 hours and 20 minutes.[3] Along with the asteroids 68 Leto and 236 Honoria, it is a member of the Leto family, a small, well-defined group of asteroids, all with a semi-major axis of close to 2.8 AU.

El Djezaïr is the French spelling of the Arabic name for Algiers, the capital of Algeria. It means "the island". The asteroid was the first minor planet to receive a name that consists of more than one word.[2] Its designation, 1916 a, is a superseded version of the modern two-letter code system of provisional designation, implemented just a few years later in 1925.


  1. ^ a b c "JPL Small-Body Database Browser: 858 El Djezair (1916 a)" (2015-08-17 last obs.). Jet Propulsion Laboratory. Retrieved 4 May 2016. 
  2. ^ a b Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names – (858) El Djezaïr. Springer Berlin Heidelberg. p. 78. ISBN 978-3-540-29925-7. Retrieved 23 October 2015. 
  3. ^ Behrend, R. (December 2007). "Asteroids and comets rotation curves—(858) El Djezair, E=2007-12-01". Geneva Observatory. Retrieved 23 October 2015. 

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