990 Yerkes

990 Yerkes
Discovery
Discovered by	G. Van Biesbroeck
Discovery site	Williams Bay
Discovery date	23 November 1922
Designations
MPC designation	(990) Yerkes
Pronunciation	/ˈjɜːrkiːz/
Alternative designations	1922 MZ
Orbital characteristics
	Epoch 31 July 2016 (JD 2457600.5)
	Uncertainty parameter 0
Observation arc	102.46 yr (37425 days)
Aphelion	3.2477 AU (485.85 Gm)
Perihelion	2.0916 AU (312.90 Gm)
Semi-major axis	2.6696 AU (399.37 Gm)
Eccentricity	0.21652
Orbital period (sidereal)	4.36 yr (1593.2 d)
Mean anomaly	216.84°
Mean motion	0° 13m 33.456s / day
Inclination	8.7872°
Longitude of ascending node	353.971°
Argument of perihelion	9.4832°
Physical characteristics
Mean radius	9.23±0.6 km
Synodic rotation period	24.56 h (1.023 d)
Sidereal rotation period	24.45 ± 0.05 h
Geometric albedo	0.1303±0.018
Absolute magnitude (H)	11.7

990 Yerkes is a main belt asteroid discovered by Belgian-American astronomer George Van Biesbroeck in 1922, and named after the Yerkes Observatory.

Photometric observations of this asteroid collected during 2009 show a rotation period of 24.45 ± 0.05 hours with a brightness variation of 0.35 ± 0.05 magnitude.^[2]

^ "990 Yerkes (1922 MZ)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 2 May 2016.
^ ^a ^b Cite error: The named reference MPB37_2_74 was invoked but never defined (see the help page).

[jpldata-1] "990 Yerkes (1922 MZ)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 2 May 2016.

[MPB37_2_74-2] Cite error: The named reference MPB37_2_74 was invoked but never defined (see the help page).

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