{{Short description|Main-belt asteroid}} {{Use dmy dates|date=October 2019}} {{Infobox planet | minorplanet= yes | mpc_name= (185) Eunike |image= Орбита астероида 185.png |caption=Orbital diagram | discoverer= C. H. F. Peters, 1878 | background= #D6D6D6 | name= 185 Eunike | alt_names= A878 EA | pronounced={{IPAc-en|j|uː|'|n|aɪ|k|iː}}<ref>Noah Webster (1884) ''A Practical Dictionary of the English Language''</ref> | adjective= Eunikean {{IPAc-en|j|uː|n|ᵻ|ˈ|k|iː|ə|n}} | named_after = Εὐνίκη ''Eynīkē'' | mp_category= Main belt | semimajor= {{Convert|2.7383|AU|Gm|abbr=on}} | perihelion= {{Convert|2.3843|AU|Gm|abbr=on}} | aphelion= {{Convert|3.0924|AU|Gm|abbr=on|lk=on}} | period= 4.53 yr (1655.1 d) | inclination= 23.238° | eccentricity= 0.12930 | dimensions= {{val|157.51|2.6|ul=km}}<ref name="jpldata"/><br />160.61 ± 5.00 km<ref name="Carry2012"/> | mass= {{nowrap|(3.56 ± 2.61) × 10<sup>18</sup> kg<ref name="Carry2012"/>}} | density= 1.64 ± 1.21 g/cm<sup>3</sup><ref name="Carry2012"/> | rotation= {{Convert|21.797|h|d|abbr=on|lk=on}}<ref name="jpldata"/><br />21.812 ± 0.001 hours<ref name="bmps41_4_244"/> | spectral_type= C | abs_magnitude= 7.62,<ref name="jpldata"/> 7.45 ± 0.01<ref name="bmps41_4_244"/> | albedo= {{val|0.0638|0.002}} | discovered= 1 March 1878 | epoch= 31 July 2016 (JD 2457600.5) | asc_node= 153.84° | arg_peri= 224.01° | mean_anomaly= 327.48° | mean_motion= {{Deg2DMS|0.21751|sup=ms}} / day | orbit_ref= <ref name="jpldata">{{Cite web |url=https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=185 |title=185 Eunike |work=JPL Small-Body Database |publisher=NASA/Jet Propulsion Laboratory |access-date=12 May 2016}}</ref> | observation_arc= 131.77 yr (48128 d) | uncertainty= 0 | moid= {{Convert|1.41759|AU|Gm|abbr=on}} | jupiter_moid= {{Convert|2.40697|AU|Gm|abbr=on}} | tisserand= 3.222 }}

'''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 {{Val|2.74|ul=AU}} with an eccentricity of 0.129 and an orbital period of 4.53&nbsp;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 {{Val|160.464|u=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.<ref name="bmps41_4_244"/>

As of 17 September 2020, there have been thirteen observed occultations of stars by Eunike.{{cn|date=March 2026}}

== References == {{Reflist|refs=

<ref name="Carry2012">{{Citation | first1 = B. | last1 = Carry | title = Density of asteroids | work = Planetary and Space Science | volume = 73 | pages = 98–118 |date=December 2012 | doi = 10.1016/j.pss.2012.03.009 | bibcode = 2012P&SS...73...98C | postscript= . | arxiv = 1203.4336 }} See Table 1.</ref>

<ref name="bmps41_4_244">{{citation | display-authors=1 | last1=Pilcher | first1=Frederick | last2=Behrend | first2=Raoul | last3=Bernasconi | first3=Laurent | last4=Franco | first4=Lorenzo | last5=Hills | first5=Kevin | last6=Martin | first6=Axel | last7=Ruthroff | first7=John C. | title=A Comprehensive Photometric Investigation of 185 Eunike | journal=of the Minor Planets Section of the Association of Lunar and Planetary Observers | date=October 2014 | volume=41 | issue=4 | pages=244&ndash;250 | bibcode=2014MPBu...41..244P | postscript=.}}</ref>

}} <!-- end of reflist -->

== External links == * {{AstDys|185}} * {{JPL small body}}

{{Minor planets navigator |184 Dejopeja |number=185 |186 Celuta}} {{Small Solar System bodies}} {{Authority control}}

{{DEFAULTSORT:000185}} Category:Background asteroids Eunike Eunike Category:Objects observed by stellar occultation Category:C-type asteroids (Tholen) Category:C-type asteroids (SMASS) 18780301