100 Hekate

100 Hekate

Discovery
Discovered by	J. C. Watson
Discovery date	July 11, 1868
Designations
Named after	Hecate
Alternate name(s)	1955 QA
Minor planet category	Main belt
Orbital characteristics
Epoch November 26, 2005 (JD 2453700.5)
Aphelion	539.149 Gm (3.604 AU)
Perihelion	386.502 Gm (2.584 AU)
Semi-major axis	462.825 Gm (3.094 AU)
Eccentricity	0.165
Orbital period	1987.636 d (5.44 a)
Average orbital speed	16.82 km/s
Mean anomaly	76.006°
Inclination	6.430°
Longitude of ascending node	127.343°
Argument of perihelion	185.908°
Proper orbital elements
Physical characteristics
Dimensions	89 km[1]
Mass	~1.0×1018 kg (estimate)
Mean density	~2.7 g/cm³ (estimate)[3]
Equatorial surface gravity	~0.033 m/s² (estimate)
Escape velocity	~0.054 km/s (estimate)
Rotation period	0.5555 d [2]
Albedo	0.192 [1]
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.

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.

References

1. ^ "IRAS Minor Planet Survey". Archived from the original on 2005-12-11. http://web.archive.org/web/20051211134758/http://www.psi.edu/pds/archive/simps.html. 
2. ^ Asteroid Lightcurve Parameters

1. PDS lightcurve data
2. G. A. Krasinsky et al. Hidden Mass in the Asteroid Belt, Icarus, Vol. 158, p. 98 (2002).