153 Hilda
Star field showing Hilda (apmag 14.2)
|
|
| Discovery | |
|---|---|
| Discovered by | J. Palisa |
| Discovery date | 2 November 1875 |
| Designations | |
| MPC designation | (153) Hilda |
| Main belt (Hilda) | |
| Orbital characteristics | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 121.05 yr (44215 d) |
| Aphelion | 4.5341 AU (678.29 Gm) |
| Perihelion | 3.4225 AU (512.00 Gm) |
| 3.9783 AU (595.15 Gm) | |
| Eccentricity | 0.13971 |
| 7.94 yr (2898.3 d) | |
| 51.690° | |
| 0° 7m 27.156s / day | |
| Inclination | 7.8249° |
| 228.16° | |
| 38.617° | |
| Earth MOID | 2.41154 AU (360.761 Gm) |
| Jupiter MOID | 0.569657 AU (85.2195 Gm) |
| Jupiter Tisserand parameter | 3.023 |
| Physical characteristics | |
| Dimensions | 170.63±3.3 km |
| Mass | ~5.2×1018 kg |
|
Equatorial escape velocity
|
~ 6 m/s |
| 5.9587 h (0.24828 d) | |
| 0.0618±0.002 | |
| C | |
| 7.48 | |
153 Hilda is a large asteroid in the outer main belt, with a diameter of 170 km. 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. The name was chosen by the astronomer Theodor von Oppolzer, who named it after one of his daughters.
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; since Jupiter takes 11.9 years to orbit the Sun while Hilda takes 7.9 years, 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.
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.
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