100 Hekate

100 Hekate

Discovery
Discovered by	J. C. Watson
Discovery date	July 11, 1868
Designations
Named after	Hecate
Alternative names	1955 QA
Minor planet category	Main belt
Orbital characteristics
Epoch April 18, 2013 (JD 2456400.5)
Aphelion	539.574 Gm (3.60683 AU)
Perihelion	384.245 Gm (2.56852 AU)
Semi-major axis	461.910 Gm (3.08768 AU)
Eccentricity	0.168
Orbital period
Mean anomaly	206.482°
Inclination	6.430°
Longitude of ascending node	127.208°
Argument of perihelion	185.029°
Physical characteristics
Dimensions	89 km
Mass	~1.0×1018 kg
Mean density	~2.7 g/cm³ (estimate)
Surface gravity	~0.033 m/s²
Escape velocity	~0.054 km/s
Rotation period	0.5555 d
Albedo	0.192
Temperature	~154 K max: 238K (-35°C)
Spectral type	S-type asteroid
Absolute magnitude (H)	7.67

100 Hekate (/ˈhɛkətiː/ HEK-ə-tee) is a large main-belt asteroid. It orbits in the same region of space as the Hygiea asteroid family, though it is actually an unrelated interloper. Its albedo of 0.19 is too high, and it is of the wrong spectral class to be part of the dark carbonaceous Hygiea family. It is listed as a member of the Hecuba group of asteroids that orbit near the 2:1 mean-motion resonance with Jupiter.

Hekate was the 100th asteroid to be discovered, by J. C. Watson (his fourth discovery) on July 11, 1868. It is named after Hecate, the goddess of witchcraft in Greek mythology, but its name also commemorates it as the hundredth asteroid, as hekaton is Greek for 'hundred'.

A Hekatean occultation of a star was observed on July 14, 2003, from New Zealand.