153 Hilda
Star field showing Hilda (apmag 14.2)
|
|
| Discovery[1] | |
|---|---|
| Discovered by | J. Palisa |
| Discovery date | 1875 |
| Designations | |
| Main belt (Hilda) | |
| Orbital characteristics[1] | |
| Aphelion | 4.533 AU |
| Perihelion | 3.412 AU |
| 3.973 AU | |
| Eccentricity | 0.141 |
| 7.92 years | |
| Inclination | 7.83° |
| Physical characteristics | |
| Dimensions | 171 ± ?? km[1] |
| Mass | ~5.2×1018 kg |
|
Equatorial escape velocity
|
~ 6 m/s |
| 5.11 hours[1] | |
| 0.062[1] | |
| C | |
| 7.48[1] | |
153 Hilda is a large asteroid in the outer main belt, with a diameter of 170 km.[1] Because it is composed of primitive carbonaceous materials, it has a very dark surface. It was discovered by Johann Palisa on November 2, 1875, from the Austrian Naval Observatory at Pula.[1] The name was chosen by the astronomer Theodor von Oppolzer, who named it after one of his daughters.[2]
Orbit and family
Hilda gives its name to an asteroid group called the Hilda family (or Hildas for short). It is not a true asteroid family, since the members are not physically related, but rather share similar orbital elements. The Hildas are locked in a 2:3 orbital resonance with Jupiter;[3] since Jupiter takes 11.9 years to orbit the Sun while Hilda takes 7.9 years,[1] Jupiter orbits the Sun twice for every 3 orbits that Hilda completes. There are over 1,100 other objects known to be in a 2:3 resonance with Jupiter.[3]
Observations
Hilda was observed to occult a star on December 31, 2002, from Japan. It has a very low-amplitude light curve indicating a spherical body or a non-varying albedo.[citation needed]
Notes
- ↑ Based on orbital data from the year 2000. Hilda seldom approaches the Lagrangians exactly.
References
External links
- Orbital simulation from JPL (Java) / Horizons Ephemeris
- The triangle formed by the Hilda asteroids EasySky
