153 Hilda

153 Hilda is a large asteroid in the outer main belt, with a diameter of 170 km.<ref name=jpldata/> The spectrum matches that of a P-type asteroid.<ref name=Lagerkvist_et_al_1995/> It was discovered by Johann Palisa on 2 November 1875, from the Austrian Naval Observatory at Pula, now Croatia.<ref name=jpldata/> The name was chosen by the astronomer Theodor von Oppolzer, who named it after one of his daughters.<ref>Template:Cite book</ref> It is the largest member of the Hilda family, a collisional family of asteroids in the Hilda region.

Orbit and family

File:HildasOrbitWithLagrangePointsLousy.ogv

Hilda gives its name to an asteroid group called the Hilda group (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;<ref name=Broz2008>Template:Cite journal</ref> since Jupiter takes 11.9 years to orbit the Sun while Hilda takes 7.9 years,<ref name=jpldata/> 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.<ref name=Broz2008/> The asteroid is, however, the largest member of the ancient physically related Hilda family within the dynamical group of the same name.

The orbital plane of 153 Hilda is inclined at an angle of 7.82° to the plane of the ecliptic. It has an orbital eccentricity (ovalness) of 0.13971.<ref name=jpldata/> Multiple light curves of the asteroid provide a consistent rotation period of approximately Template:Val<ref name=Pilcher_2020/>

Notes

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External links

• The triangle formed by the Hilda asteroids EasySky
• Template:AstDys
• Template:JPL small body