 Star field showing Hilda (apmag 14.2) | |
| Discovery[1] | |
|---|---|
| Discovered by | J. Palisa |
| Discovery site | Austrian Naval Obs. |
| Discovery date | 2 November 1875 |
| Designations | |
| (153) Hilda | |
| Pronunciation | /ˈhɪldə/[2] |
| A875 VC; 1935 GD | |
| Main belt (Hilda) | |
| Adjectives | Hildian/ˈhɪldiən/[3] |
| Orbital characteristics[1] | |
| 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 |
| 7.935 yr (2,898.3 d) 7.94yr (2898.3d) | |
| 51.690° | |
| 0° 7m 27.156s / day | |
| Inclination | 7.8249° |
| 228.16° | |
| 38.617° | |
| Jupiter MOID | 0.569657 AU (85.2195 Gm) |
| TJupiter | 3.023 |
| Physical characteristics | |
| Dimensions | 170.63±3.3 km[1] |
| Mass | ~5.2×1018 kg |
Equatorialescape velocity | ~ 6 m/s |
| 5.9587 h (0.24828 d)[1] | |
| 0.0618±0.002[1] | |
| P[4] | |
| 7.48[1] | |
153 Hilda is a largeasteroid in the outermain belt, with a diameter of 170 km.[1] The spectrum matches that of aP-type asteroid.[4] It was discovered byJohann Palisa on 2 November 1875, from theAustrian Naval Observatory at Pula, now Croatia.[1] The name was chosen by the astronomerTheodor von Oppolzer, who named it after one of his daughters.[5] It is the largest member of theHilda family, a collisional family of asteroids in the Hilda region.
Hilda gives its name to an asteroid group called theHilda group (orHildas for short). It is not a trueasteroid family, since the members are not physically related, but rather share similar orbital elements. The Hildas are locked in a 2:3orbital resonance withJupiter;[6] 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.[6] The asteroid is, however, the largest member of the ancient physically relatedHilda family within the dynamical group of the same name.
Theorbital plane of 153 Hilda isinclined at an angle of 7.82° to the plane of theecliptic. It has anorbital eccentricity (ovalness) of 0.13971.[1] Multiplelight curves of the asteroid provide a consistentrotation period of approximately5.9585 h[7]
