(153) Hilda

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(153) Hilda
Properties of the orbit ( animation )
Orbit type Outer main belt
Asteroid family Hilda family
Major semi-axis 3,972  AU
eccentricity 0.138
Perihelion - aphelion 3.423 AU - 4.521 AU
Inclination of the orbit plane 7.8 °
Length of the ascending node 228.2 °
Argument of the periapsis 39.1 °
Time of passage of the perihelion July 16, 2007
Sidereal period 7 a 335 d
Mean orbital velocity 14.9 km / s
Physical Properties
Medium diameter 171 km
Albedo 0.0618
Rotation period 5 h 58 min
Absolute brightness 7.48 likes
Spectral class P
Explorer J. Palisa
Date of discovery November 2, 1875
Another name 1935 GD
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.

(153) Hilda is an asteroid of the outer main asteroid belt discovered by Johann Palisa on November 2, 1875 . The celestial body was named in memory of the eldest daughter of the astronomer Theodor von Oppolzer , who had died a year earlier.

Hilda moves between 3.423 ( perihelion ) astronomical units to 4.551 astronomical units ( aphelion ) in 7.96 years around the sun . The orbit is inclined 7.839 ° to the ecliptic , the orbit eccentricity is 0.141.

Hilda has a diameter of 171 km. It has a dark carbon-rich surface with an albedo of 0.062. It rotates around its own axis in around 5 hours and 7 minutes.

Star occultation was observed from Japan at the end of 2002 . Hilda passed exactly in front of a star (seen from earth) and darkened its light. Based on the different course of the light curve at different observation points, it could be concluded that Hilda is a round body.

Hilda group

Scheme of the orbit of (153) Hilda (green), Jupiter (red) and the Lagrange points of Jupiter (open red circles)
Representation of the inner solar system. Golden the Hildas .

Hilda is the namesake of a group of asteroids that move in an orbital resonance of 3: 2 with the planet Jupiter around the sun. What they have in common is a mean distance from the sun between 3.7 and 4.2 AU, an eccentricity of less than 0.3 and an inclination less than 20 °. If you look at the distribution of the Hilda group, you can see a triangle rotating with Jupiter (which is near the center of one of the edges). This is a dynamic phenomenon that arises from the 3: 2 resonance, because of course none of the asteroids moves on a triangular orbit. But their ellipses are so interwoven in terms of time and space that a triangular distribution of the Hilda group always occurs.

See also

Individual evidence

  1. ^ Lutz D. Schmadel, Dictionary of Minor Planet Names , p.29 .