122 Gerda

122 Gerda

Discovery
Discovered by	Christian Heinrich Friedrich Peters
Discovery date	July 31, 1872
Designations
Alternative names
Minor planet category	Main belt
Orbital characteristics
Epoch December 31, 2006 (JD 2454100.5)
Aphelion	501.593 Gm (3.353 AU)
Perihelion	462.356 Gm (3.091 AU)
Semi-major axis	481.975 Gm (3.222 AU)
Eccentricity	0.041
Orbital period	2112.255 d (5.78 a)
Average orbital speed	16.59 km/s
Mean anomaly	283.072°
Inclination	1.639°
Longitude of ascending node	178.433°
Argument of perihelion	325.878°
Physical characteristics
Dimensions	81.7 km
Mass	5.7×1017 kg
Surface gravity	0.0228 m/s²
Escape velocity	0.0432 km/s
Rotation period	10.687 ± 0.001 h
Temperature	~155 K
Spectral type	S
Absolute magnitude (H)	7.87

122 Gerda is a fairly large outer main-belt asteroid that was discovered by German-American astronomer C. H. F. Peters on July 31, 1872, and named after Gerðr, the wife of the god Freyr in Norse mythology. Based upon its spectrum, this is classified as an S-type asteroid. It is listed as a member of the Hecuba group of asteroids that orbit near the 2:1 mean-motion resonance with Jupiter.

Photometric observations of this asteroid in 2007 were used to produce a light curve that showed that Gerda rotates every 10.687 ± 0.001 hours and varied in brightness by 0.16 in magnitude. In 2009, observations at the Organ Mesa Observatory in Las Cruces, New Mexico generated a light curve with a period of 10.712 ± 0.01 hours with a brightness variation of 0.11 ± 0.01 magnitudes. This is compatible with previous studies.

See also

• List of minor planets: 1–1000