999 Zachia

999 Zachia
Discovery
Discovered by	K. Reinmuth
Discovery site	Heidelberg
Discovery date	9 August 1923
Designations
MPC designation	(999) Zachia
Alternative designations	1923 NW
Orbital characteristics
	Epoch 31 July 2016 (JD 2457600.5)
	Uncertainty parameter 0
Observation arc	92.68 yr (33850 days)
Aphelion	3.1787 AU (475.53 Gm)
Perihelion	2.0450 AU (305.93 Gm)
Semi-major axis	2.6118 AU (390.72 Gm)
Eccentricity	0.21704
Orbital period (sidereal)	4.22 yr (1541.8 d)
Mean anomaly	352.050°
Mean motion	0° 14m 0.6s / day
Inclination	9.7603°
Longitude of ascending node	214.972°
Argument of perihelion	128.034°
Physical characteristics
Mean radius	8.95 km
Synodic rotation period	22.77 h (0.949 d)
Geometric albedo	0.1994±0.051
Absolute magnitude (H)	10.8

999 Zachia is a main-belt asteroid that was discovered by German astronomer Karl W. Reinmuth in 1923 and named after Hungarian astronomer Franz Xaver von Zach.

Photometric observations of this asteroid collected during 1999 show a rotation period of 22.77 ± 0.03 hours with a brightness variation of 0.3 magnitude.^[2]

^ "999 Zachia (1923 NW)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 2 May 2016.
^ Cite error: The named reference MPB27_4 was invoked but never defined (see the help page).

[jpldata-1] "999 Zachia (1923 NW)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 2 May 2016.

[MPB27_4-2] Cite error: The named reference MPB27_4 was invoked but never defined (see the help page).

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