69 Hesperia

69 Hesperia
A three-dimensional model of 69 Hesperia based on its light curve.
Discovery
Discovered byG. Schiaparelli
Discovery dateApril 29, 1861[1]
Designations
(69) Hesperia
Pronunciation/hɛˈspɪəriə/[2]
Named after
Hesperia
Main belt
AdjectivesHesperian /hɛˈspɪəriən/[3]
Orbital characteristics
Epoch (absent)
Aphelion3.471 AU (519.3 Gm)
Perihelion2.489 AU (372.3 Gm)
2.980 AU (445.8 Gm)
Eccentricity0.165
1,879 days (5.14 a)
Inclination8.59°
184.99°
288.8°
Physical characteristics
Dimensions138 km (IRAS)[4]
110 ± 15 km[5]
Mass(5.86±1.18)×1018 kg[6]
Mean density
4.38±0.99 g/cm3[6]
5.655 h[4]
0.140[4]
M
7.05[4]

69 Hesperia is a large, M-type main-belt asteroid. It was discovered by the Italian astronomer Giovanni Schiaparelli on April 29, 1861[1] from Milan, while he was searching for the recently discovered 63 Ausonia.[7] It was his only asteroid discovery. Schiaparelli named it Hesperia in honour of Italy (the word is a Greek term for the peninsula).[8] The asteroid is orbiting the Sun with a period of 5.14 years, a semimajor axis of 2.980 AU, and eccentricity of 0.165. The orbital plane is inclined by an angle of 8.59° to the plane of the ecliptic.

Hesperia was observed by Arecibo radar in February 2010.[5] Radar observations combined with lightcurve-based shape models, lead to a diameter estimate of 110 ± 15 km (68 ± 9.3 mi). The radar albedo is consistent with a high-metal M-type asteroid.[5] In the near infrared, a weak absorption feature near a wavelength of 0.9 μm can be attributed to orthopyroxenes on the surface.[9] A meteorite analogue of the reflectance spectra from 69 Hesperia is the Hoba ataxite.[10]

  1. ^ a b Cite error: The named reference MPC94743 was invoked but never defined (see the help page).
  2. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  3. ^ "Hesperian". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  4. ^ a b c d Cite error: The named reference jpldata was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Shepard2011 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Carry2012 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference DeMeis2011 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Schmadel2003 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Hardersen2005 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Neeley2014 was invoked but never defined (see the help page).