153 Hilda
Star field showing Hilda (apmag 14.2)
|
|
|
Discovery[1] and designation
|
|
|---|---|
| Discovered by | J. Palisa |
| Discovery date | 1875 |
|
Designations
|
|
| Minor planet category |
Main belt (Hilda) |
| Aphelion | 4.533 AU |
| Perihelion | 3.412 AU |
| Semi-major axis | 3.973 AU |
| Eccentricity | 0.141 |
| Orbital period | 7.92 years |
| Inclination | 7.83° |
| Dimensions | 170.63 km[1] |
| Mass | ~1.5×1015 kg |
| Equatorial escape velocity | ~ 6 m/s |
| Rotation period | 5.11 hours[1] |
| Geometric albedo | 0.062[1] |
| Spectral type | C |
| Absolute magnitude (H) | 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]
Contents |
[edit] 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]
[edit] 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]
[edit] Notes
- ^ Based on orbital data from the year 2000. Hilda seldom approaches the Lagrangians exactly.
[edit] References
- ^ a b c d e f g h i "JPL Small-Body Database Browser: 153 Hilda". 1998-02-12 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Hilda. Retrieved 2009-12-15.
- ^ Lutz D. Schmadel, Dictionary of Minor Planet Names, p.29.
- ^ a b Brož, M.; Vokrouhlický, D. (2008). "Asteroid families in the first-order resonances with Jupiter". Monthly Notices of the Royal Astronomical Society 390 (2): 715–732. Bibcode 2008MNRAS.tmp.1068B. doi:10.1111/j.1365-2966.2008.13764.x.
[edit] External links
- Orbital simulation from JPL (Java) / Horizons Ephemeris
- The triangle formed by the Hilda asteroids EasySky
|
|||||
|
||||||||||||||||||||||
_mathilde.jpg){kind=small} |
This article about a C-type asteroid native to the main belt is a stub. You can help Wikipedia by expanding it. |
