69 Hesperia

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69 Hesperia
69Hesperia (Lightcurve Inversion).png
A three-dimensional model of 69 Hesperia based on its light curve.
Discovered by G. Schiaparelli
Discovery date April 29, 1861[1]
MPC designation (69) Hesperia
Pronunciation /hɛsˈpɪəriə/
Named after
Main belt
Orbital characteristics
Epoch (absent)
Aphelion 3.471 AU (519.3 Gm)
Perihelion 2.489 AU (372.3 Gm)
2.980 AU (445.8 Gm)
Eccentricity 0.165
1,879 days (5.14 a)
Inclination 8.59°
Physical characteristics
Dimensions 138 km (IRAS)[2]
135x106x98 km[3]
110 ± 15 km[3]
Mass (5.86±1.18)×1018 kg[4]
Mean density
4.38±0.99 g/cm3[4]
5.655 h[2]

69 Hesperia (/hɛsˈpɪəriə/ hes-PEER-ee-ə) is a large, M-type main-belt asteroid. It was discovered by the Italian astronomer Giovanni Schiaparelli on April 29, 1861[1] from Milan. It was his only asteroid discovery. Schiaparelli named it Hesperia in honour of Italy (the word is a Greek term for the peninsula).[5]

Hesperia was observed by Arecibo radar in February 2010.[3] Radar observations combined with lightcurve-based shape models, lead to a diameter estimate of 110 ± 15 km (68 ± 9.3 mi).[3] In the near infrared, a weak absorption feature near a wavelength of 0.9 μm can be attributed to orthopyroxenes on the surface.[6] A meteorite analogue of the reflectance spectra from 69 Hesperia is the Hoba ataxite.[7]


  1. ^ a b "Editorial Notice" (PDF). The Minor Planet Circulars. MPC 94743-95312: 94743. 2015-08-29. Retrieved 4 September 2015. 
  2. ^ a b c d "JPL Small-Body Database Browser: 69 Hesperia" (2011-09-07 last obs). Jet Propulsion Laboratory. Retrieved 2012-01-27. 
  3. ^ a b c d Shepard, Michael K.; Harris, Alan W.; Taylor, Patrick A.; Clark, Beth Ellen; Ockert-Bell, Maureen; Nolan, Michael C.; et al. (2011). "Radar observations of Asteroids 64 Angelina and 69 Hesperia" (PDF). Icarus. 215 (2): 547–551. Bibcode:2011Icar..215..547S. doi:10.1016/j.icarus.2011.07.027. 
  4. ^ a b Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73, pp. 98–118, arXiv:1203.4336Freely accessible, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009.  See Table 1.
  5. ^ Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names. Springer Science & Business Media. p. 22. ISBN 978-3-540-00238-3. 
  6. ^ Hardersen, Paul S.; et al. (May 2005), "Near-IR spectral evidence for the presence of iron-poor orthopyroxenes on the surfaces of six M-type asteroids", Icarus, 175 (1): 141−158, Bibcode:2005Icar..175..141H, doi:10.1016/j.icarus.2004.10.017. 
  7. ^ Neeley, J. R.; et al. (August 2014), "The composition of M-type asteroids II: Synthesis of spectroscopic and radar observations", Icarus, 238: 37−50, arXiv:1407.0750Freely accessible, Bibcode:2014Icar..238...37N, doi:10.1016/j.icarus.2014.05.008. 

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