Astronomy:185 Eunike
 Orbital diagram | |
| Discovery | |
|---|---|
| Discovered by | C. H. F. Peters, 1878 |
| Discovery date | 1 March 1878 |
| Designations | |
| (185) Eunike | |
| Pronunciation | /juːˈnaɪkiː/[1] |
| Named after | Εὐνίκη Eynīkē |
| A878 EA | |
| Minor planet category | Main belt |
| Adjectives | Eunikean /juːnɪˈkiːən/ |
| Orbital characteristics[2] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 131.77 yr (48128 d) |
| |{{{apsis}}}|helion}} | 3.0924 astronomical unit|AU (462.62 Gm) |
| |{{{apsis}}}|helion}} | 2.3843 AU (356.69 Gm) |
| 2.7383 AU (409.64 Gm) | |
| Eccentricity | 0.12930 |
| Orbital period | 4.53 yr (1655.1 d) |
| Mean anomaly | 327.48° |
| Mean motion | 0° 13m 3.036s / day |
| Inclination | 23.238° |
| Longitude of ascending node | 153.84° |
| 224.01° | |
| Earth MOID | 1.41759 AU (212.068 Gm) |
| Jupiter MOID | 2.40697 AU (360.078 Gm) |
| TJupiter | 3.222 |
| Physical characteristics | |
| Dimensions | 157.51±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] |
| Rotation period | 21.797 h (0.9082 d)[2] 21.812 ± 0.001 hours[4] |
| Geometric albedo | 0.0638±0.002 |
| C | |
| Absolute magnitude (H) | 7.62,[2] 7.45 ± 0.01[4] |
185 Eunike is a dark and very large main-belt asteroid. 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).
This object is orbiting the Sun at a distance of 2.74 astronomical unit|AU with an eccentricity of 0.129 and an orbital period of 4.53 years. Its orbital plane is inclined at an angle of 23.2° to the plane of the ecliptic. Using infrared measurements, the diameter has been measured at 160.464 km. It has a primitive carbonaceous composition.
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.[citation needed]
References
- ↑ Noah Webster (1884) A Practical Dictionary of the English Language
- ↑ 2.0 2.1 2.2 2.3 "185 Eunike". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=185.
- ↑ 3.0 3.1 3.2 Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73: pp. 98–118, doi:10.1016/j.pss.2012.03.009, Bibcode: 2012P&SS...73...98C. See Table 1.
- ↑ 4.0 4.1 4.2 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.
External links
- 185 Eunike at AstDyS-2, Asteroids—Dynamic Site
- 185 Eunike at the JPL Small-Body Database
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