108 Hecuba
Hecuba (minor planet designation: 108 Hecuba) is a fairly large and bright main-belt asteroid. It was discovered by Karl Theodor Robert Luther on 2 April 1869, and named after Hecuba, wife of King Priam in the legends of the Trojan War in Greek Mythology. This object is orbiting the Sun with a period of 5.83 years and an eccentricity of 0.06. It became the first asteroid discovered to orbit near a 2:1 mean-motion resonance with the planet Jupiter, and is the namesake of the Hecuba group of asteroids.
Orbital diagram | |||||||||||||
| Discovery | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Discovered by | R. Luther | ||||||||||||
| Discovery date | 2 April 1869 | ||||||||||||
| Designations | |||||||||||||
MPC designation | (108) Hecuba | ||||||||||||
| Pronunciation | /ˈhɛkjʊbə/ | ||||||||||||
Named after | Hecuba | ||||||||||||
Minor planet category | Main belt | ||||||||||||
| Orbital characteristics | |||||||||||||
| Epoch 31 July 2016 (JD 2457600.5) | |||||||||||||
| Uncertainty parameter 0 | |||||||||||||
| Observation arc | 135.87 yr (49628 d) | ||||||||||||
| Aphelion | 3.4190 AU (511.48 Gm) | ||||||||||||
| Perihelion | 3.05922 AU (457.653 Gm) | ||||||||||||
Semi-major axis | 3.23912 AU (484.565 Gm) | ||||||||||||
| Eccentricity | 0.055539 | ||||||||||||
Orbital period (sidereal) | 5.83 yr (2129.3 d) | ||||||||||||
Average orbital speed | 16.53 km/s | ||||||||||||
Mean anomaly | 166.649° | ||||||||||||
Mean motion | 0° 10m 8.648s / day | ||||||||||||
| Inclination | 4.2204° | ||||||||||||
Longitude of ascending node | 350.014° | ||||||||||||
| 204.634° | |||||||||||||
| Earth MOID | 2.05833 AU (307.922 Gm) | ||||||||||||
| Jupiter MOID | 1.55152 AU (232.104 Gm) | ||||||||||||
| TJupiter | 3.178 | ||||||||||||
| Physical characteristics | |||||||||||||
| Dimensions | 64.97±4.4 km 65 km | ||||||||||||
| Mass | ~3.9×1017 kg (estimate) | ||||||||||||
Mean density | ~2.7 g/cm3 (estimate) | ||||||||||||
Equatorial surface gravity | ~0.025 m/s² (estimate) | ||||||||||||
Equatorial escape velocity | ~0.040 km/s (estimate) | ||||||||||||
Synodic rotation period | 14.256 h (0.5940 d) 0.60 d or 1.20 d | ||||||||||||
| 0.2431±0.037 | |||||||||||||
| |||||||||||||
| S | |||||||||||||
| 8.09 | |||||||||||||
In the Tholen classification system, it is categorized as a stony S-type asteroid, while the Bus asteroid taxonomy system lists it as an Sw asteroid. Observations performed at the Palmer Divide Observatory in Colorado Springs, Colorado in during 2007 produced a light curve with a period of 17.859 ± 0.005 hours with a brightness variation of 0.11 ± 0.02 in magnitude.
Hecuba orbits within the Hygiea family of asteroids but is not otherwise related to other family members because it has a silicate composition; Hygieas are dark C-type asteroids.