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185 Eunike

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185 Eunike
Orbital diagram
Discovery
Discovered byC. H. F. Peters, 1878
Discovery date1 March 1878
Designations
(185) Eunike
Pronunciation/jˈnk/[1]
Named after
Εὐνίκη Eynīkē
A878 EA
Main belt
AdjectivesEunikean /jnɪˈkən/
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc131.77 yr (48128 d)
Aphelion3.0924 AU (462.62 Gm)
Perihelion2.3843 AU (356.69 Gm)
2.7383 AU (409.64 Gm)
Eccentricity0.12930
4.53 yr (1655.1 d)
327.48°
0° 13m 3.036s / day
Inclination23.238°
153.84°
224.01°
Earth MOID1.41759 AU (212.068 Gm)
Jupiter MOID2.40697 AU (360.078 Gm)
TJupiter3.222
Physical characteristics
Dimensions157.51±2.6 km[2]
160.61 ± 5.00 km[3]
Mass(3.56 ± 2.61) × 1018 kg[3]
Mean density
1.64 ± 1.21 g/cm3[3]
21.797 h (0.9082 d)[2]
21.812 ± 0.001 hours[4]
0.0638±0.002
C
7.62,[2] 7.45 ± 0.01[4]

185 Eunike is a dark and very large main-belt asteroid, with an approximate diameter of 157 kilometres. It has a primitive carbonaceous composition.

It was discovered by C. H. F. Peters on March 1, 1878, in Clinton, New York and named after Eunike, a Nereid in Greek mythology whose name means 'happy victory'. The name was chosen to celebrate the Treaty of San Stefano (1878).

Based upon photometric observations made between 2010 and 2014, this asteroid has a rotation period of 21.812 ± 0.001 hours and a brightness variation of 0.08 ± 0.01 in magnitude. At opposition, the absolute magnitude was measured at 7.45 ± 0.01. It displays a hemispheric albedo dichotomy similar to that on 4 Vesta.[4]

As of 17 September 2020, there have been thirteen observed occultations of stars by Eunike.

References

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  1. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  2. ^ a b c d "185 Eunike". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 12 May 2016.
  3. ^ a b c Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
  4. ^ a b c Pilcher, Frederick; et al. (October 2014), "A Comprehensive Photometric Investigation of 185 Eunike", of the Minor Planets Section of the Association of Lunar and Planetary Observers, 41 (4): 244–250, Bibcode:2014MPBu...41..244P.
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