153 Hilda

153 Hilda
Star field showing Hilda (apmag 14.2)
Discovery[1]
Discovered byJ. Palisa
Discovery siteAustrian Naval Obs.
Discovery date2 November 1875
Designations
(153) Hilda
Pronunciation/ˈhɪldə/[2]
A875 VC; 1935 GD
Main belt (Hilda)
AdjectivesHildian /ˈhɪldiən/[3]
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc121.05 yr (44215 d)
Aphelion4.5341 AU (678.29 Gm)
Perihelion3.4225 AU (512.00 Gm)
3.9783 AU (595.15 Gm)
Eccentricity0.13971
7.935 yr (2,898.3 d) 7.94 yr (2898.3 d)
51.690°
0° 7m 27.156s / day
Inclination7.8249°
228.16°
38.617°
Jupiter MOID0.569657 AU (85.2195 Gm)
TJupiter3.023
Physical characteristics
Dimensions170.63±3.3 km[1]
Mass~5.2×1018 kg
Equatorial escape 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 large asteroid in the outer main belt, with a diameter of 170 km.[1] The spectrum matches that of a P-type asteroid.[4] It was discovered by Johann Palisa on 2 November 1875, from the Austrian Naval Observatory at Pula, now Croatia.[1] The name was chosen by the astronomer Theodor von Oppolzer, who named it after one of his daughters.[5] It is the largest member of the hilda family, a collisional family of asteroids in the Hilda region.

Orbit and family

A schematic of the orbit of 153 Hilda (green), with Jupiter (red). The open red circles are the Jovian Lagrange points that Hilda approaches.[note 1]

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;[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 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.[1] Multiple light curves of the asteroid provide a consistent rotation period of approximately 5.9585 h[7]

Notes

  1. ^ Based on orbital data from the year 2000. Hilda seldom approaches the Lagrangians exactly.

References

  1. ^ a b c d e f g h i j "JPL Small-Body Database Browser: 153 Hilda". 12 February 1998. Retrieved 12 May 2016.
  2. ^ "Hilda". Dictionary.com Unabridged (Online). n.d.
  3. ^ Bhattacharya & Lichtman (2016) Solar Planetary Systems, p. 6
  4. ^ a b Lagerkvist, C. -I.; et al. (December 1995). "Physical Studies of Asteroids XXX: The Asteroid 153 Hilda". Earth, Moon, and Planets. 71 (3): 189–194. Bibcode:1995EM&P...71..189L. doi:10.1007/BF00612956. S2CID 120302355.
  5. ^ Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names. Springer Science & Business Media. p. 29. ISBN 978-3-540-00238-3.
  6. ^ 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. arXiv:1104.4004. Bibcode:2008MNRAS.390..715B. doi:10.1111/j.1365-2966.2008.13764.x. S2CID 53965791.
  7. ^ Pilcher, Frederick (July 2020). "Lightcurves and Rotation Periods of 83 Beatrix, 86 Semele, 118 Peitho 153 Hilda, 527 Euryanthe, and 549 Jessonda". Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers. 47 (3): 192–195. Bibcode:2020MPBu...47..192P.