100 Hekate

100 Hekate

orbit
Discovery
Discovered by	J. C. Watson
Discovery date	11 July 1868
Designations
MPC designation	(100) Hekate
Pronunciation	/ˈhɛkətiː/[1]
Named after	Hecate
Alternative designations	1955 QA
Minor planet category	Main belt
Adjectives	Hekatean (Hecatæan) /hɛkəˈtiːən/[1]
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	144.93 yr (52936 d)
Aphelion	3.61005 AU (540.056 Gm)
Perihelion	2.56919 AU (384.345 Gm)
Semi-major axis	3.08962 AU (462.201 Gm)
Eccentricity	0.16844
Orbital period (sidereal)	5.43 yr (1983.6 d)
Mean anomaly	64.6430°
Mean motion	0° 10m 53.357s / day
Inclination	6.42957°
Longitude of ascending node	127.199°
Argument of perihelion	184.736°
Earth MOID	1.55453 AU (232.554 Gm)
Jupiter MOID	1.66378 AU (248.898 Gm)
TJupiter	3.194
Physical characteristics
Dimensions	88.66±2.0 km[2] 89 km[3]
Mass	~1.0×1018 kg
Mean density	~2.7 g/cm3 (estimate)[4]
Equatorial surface gravity	~0.033 m/s2
Equatorial escape velocity	~0.054 km/s
Synodic rotation period	27.066 h (1.1278 d)[2] 0.5555 d[5]
Geometric albedo	0.1922±0.009[2] 0.192[3]
Temperature	~154 K max: 238K (-35°C)
Spectral type	S-type asteroid
Absolute magnitude (H)	7.67

100 Hekate is a large main-belt asteroid.

This is a stony S-type asteroid with a diameter of 87+5
−4 km and a sidereal rotation period of 27.07 h.^[6] It orbits in the same region of space as the Hygiea asteroid family, though it is actually an unrelated interloper. However, its geometric albedo of 0.22±0.03^[6] 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.^[7]

Hekate was the 100th asteroid to be discovered, by Canadian-American astronomer J. C. Watson (his fourth discovery) on July 11, 1868.^[8] It is named after Hecate, the goddess of witchcraft in Greek mythology, but its name also commemorates it as the hundredth asteroid, as ἑκατόν (hekaton) is Greek for 'hundred'.

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

• List of minor planets: 1–1000
• 100000 Astronautica

• 100 Hekate at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 100 Hekate at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters