# 164 Eva

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{{Short description|Main-belt asteroid}}
{{Use dmy dates|date=October 2019}}
{{Infobox planet
 | minorplanet=yes
 | background=#D6D6D6
 | name=164 Eva
|image= 000164-asteroid shape model (164) Eva.png
|caption= 3D convex shape model of 164 Eva
 | discovery_ref=
 | discoverer=[P. P. Henry](/source/Paul_Henry_(astronomer))
 | discovery_site=[Paris](/source/Paris)
 | discovered=12 July 1876
 | mpc_name=(164) Eva
 | alt_names=A876 NA
 | pronounced={{IPAc-en|'|iː|v|ə}}<ref>{{dict.com|Eva}}</ref>
 | named_after=Unknown
 | mp_category=[Main belt](/source/Asteroid_belt)
 | orbit_ref=<ref name="JPL"/>
 | epoch=31 July 2016 ([JD](/source/Julian_day) 2457600.5)
 | semimajor={{Convert|2.6338|AU|Gm|abbr=on}}
 | perihelion={{Convert|1.7188|AU|Gm|abbr=on}}
 | aphelion={{Convert|3.5444|AU|Gm|abbr=on|lk=on}}
 | eccentricity=0.34577
 | period=4.27 [yr](/source/Julian_year_(astronomy)) (1561.2 [d](/source/Julian_year_(astronomy)))
 | inclination=24.4564°
 | asc_node=76.8519°
 | arg_peri=283.9561°
 | mean_anomaly=219.5472[°](/source/Degree_(angle))
 | avg_speed=
 | dimensions={{val|104.87|1.9|ul=km}}<ref name="JPL"/><br />101.77 ± 3.61 km<ref name="Carry2012"/>
 | mass={{nowrap|(9.29 ± 7.76) × 10<sup>17</sup> kg<ref name="Carry2012"/>}}
 | density=1.68 ± 1.41 g/cm<sup>3</sup><ref name="Carry2012"/>
 | surface_grav=2.249 cm/s (mean)
 | escape_velocity=4.857 cm/s (mean)
 | rotation={{Convert|13.66|h|d|abbr=on|lk=on}}<ref name="JPL"/><br />13.672 h<ref name="Warner2009"/>
 | spectral_type=[C](/source/C-type_asteroid)
 | magnitude=
 | abs_magnitude=8.89,<ref name="JPL"/> 8.84<ref name="Warner2007"/>
 | albedo={{val|0.0447|0.002}}
 | single_temperature=170 K (mean)
 | mean_motion={{Deg2DMS|0.230591|sup=ms}} / day
 | observation_arc=118.93 yr (43438 d)
 | uncertainty=0
 | moid={{Convert|0.882286|AU|Gm|abbr=on}}
 | jupiter_moid={{Convert|2.44116|AU|Gm|abbr=on}}
 | tisserand=3.191
}}

'''164 Eva''' is a [main-belt](/source/Asteroid_belt) [asteroid](/source/asteroid) that was discovered by the French brothers [Paul Henry and Prosper Henry](/source/Paul_Henry_and_Prosper_Henry) on July 12, 1876, in Paris. The reason the name Eva was chosen remains unknown, though [Karl Ludwig Littrow](/source/Karl_Ludwig_Littrow) suspected a "worldly origin" (''"Mit dem Namen könnten wir wie bei [Miriam](/source/102_Miriam) wieder den biblischen Boden zu betreten glauben, wenn wir bei diesem Entdecker nicht an Taufen weltlichen Ursprungs gewöhnt wären"'').<ref name="Schmadel2012"/> The [orbital elements](/source/orbital_elements) for 164 Eva were published in 1877 by American astronomer [Winslow Upton](/source/Winslow_Upton).<ref name="Upton1877"/>

This asteroid is categorized as a [C-type asteroid](/source/C-type_asteroid) and is probably composed of primitive [carbonaceous](/source/carbonate) [chondritic](/source/chondrite) materials. Dust activity due to [sublimation](/source/Sublimation_(phase_transition)) has been detected on this asteroid, suggesting the presence of water [ice](/source/ice) in its interior.<ref name=Busarev_et_al_2024/>

This object has an estimated diameter of around {{Val|105|u=km}}. [Photometric](/source/Photometry_(astronomy)) observations of this asteroid at the Palmer Divide Observatory in [Colorado Springs, Colorado](/source/Colorado_Springs%2C_Colorado), during 2008 gave a [light curve](/source/light_curve) with a period of 13.672 ± 0.003 hours and a small brightness variation of 0.04 ± 0.01 in [magnitude](/source/Magnitude_(astronomy)). This is consistent with a previous study reported in 1982 that listed a period estimate of 13.66 hours.<ref name="Warner2009"/>

Between 2000 and 2021, 164 Eva has been observed to [occult](/source/occultation) fourteen stars.{{cn|date=March 2026}}

164 Eva is orbiting the Sun at a distance of {{Val|2.63|u=km}} with an [eccentricity](/source/orbital_eccentricity) of 0.35 and an [orbital period](/source/orbital_period) of 4.27&nbsp;years. The [orbital plane](/source/orbital_plane) is inclined at an angle of 24.5° to the [plane of the ecliptic](/source/plane_of_the_ecliptic). With a perihelion of 1.718 AU 164 Eva is the closest asteroid with a diameter over 100 kilometers to approach the [orbit of Mars](/source/orbit_of_Mars). Its closest approach is about 0.05 AU or about 19.5 lunar distances.<ref>[https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=164 NASA.gov]</ref>

==References==
{{Reflist|refs=

<ref name="JPL">{{Citation
 | first1    = Donald K.
 | last1     = Yeomans
 | title     = 164 Eva
 | work      = JPL Small-Body Database
 | url       = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=164
 | archive-url = https://web.archive.org/web/20190304133020/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=164
 | url-status = dead
 | archive-date = 4 March 2019
 | accessdate= 12 May 2016
 | postscript= .}}</ref>

<ref name="Upton1877">{{Citation
 | last1     = Upton
 | first1    = Winslow
 | title     = Elements of (164) Eva
 | journal      = Astronomische Nachrichten
 | volume    = 90
 | issue = 6
 | pages     = 85–86
 |date=July 1877
 | doi       = 10.1002/asna.18770900605
 | bibcode   = 1877AN.....90...85U
 | postscript= .| url = https://zenodo.org/record/1424701
 }}</ref>

<ref name="Carry2012">{{Citation
 | first1    = B.
 | last1     = Carry
 | title     = Density of asteroids
 | journal      = Planetary and Space Science
 | volume    = 73
 | issue = 1
 | 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="Warner2007">{{Citation
 | last1     = Warner
 | first1    = Brian D.
 | title     = Initial Results of a Dedicated H-G Project
 | journal      = The Minor Planet Bulletin
 | volume    = 34
 | issue = 4
 | pages     = 113–119
 |date=December 2007
 | bibcode   = 2007MPBu...34..113W
 | postscript= .}}</ref>

<ref name="Schmadel2012">{{Citation
 | first1    = Lutz D.
 | last1     = Schmadel
 | title     = Dictionary of Minor Planet Names
 | publisher = Springer
 | pages      = 28, 1341
 | year      = 2012
 | isbn      = 978-3642297182
 | url       = https://books.google.com/books?id=aeAg1X7afOoC&pg=PA1341 | postscript= .}}</ref>

<ref name="Warner2009">{{Citation
 | last1     = Warner
 | first1    = Brian D.
 | title     = Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2008 May - September
 | journal      = The Minor Planet Bulletin
 | volume    = 36
 | issue     = 1
 | pages     = 7–13
 |date=January 2009
 | bibcode   = 2009MPBu...36....7W
 | postscript= .}}</ref>

<ref name=Busarev_et_al_2024>{{cite journal
 | title=Sublimation-Driven Dust Activity of Primitive-Type Asteroids as a Sign of the Presence of H<sub>2</sub>O Ice
 | last1=Busarev | first1=V. V. | last2=Petrova | first2=E. V.
 | last3=Shcherbina | first3=M. P. | last4=Burlak | first4=M. A.
 | last5=Ikonnikova | first5=N. P. | last6=Maksimova | first6=M. V.
 | display-authors=1 | journal=Solar System Research
 | volume=58 | issue=6 | pages=715–731 | date=December 2024
 | doi=10.1134/S0038094624700503 | bibcode=2024SoSyR..58..715B }}</ref>

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

== External links ==
* {{usurped|1=[https://web.archive.org/web/20230204083603/https://www.minorplanetobserver.com/pdolc/A164_2008.HTM Lightcurve plot of 164 Eva]}}, Palmer Divide Observatory, ''[B. D. Warner](/source/Brian_D._Warner)'' (2008)
* [http://www.minorplanet.info/PHP/lcdbsummaryquery.php Asteroid Lightcurve Database (LCDB)], query form ([http://www.minorplanet.info/lightcurvedatabase.html info] {{Webarchive|url=https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html |date=16 December 2017 }})
* [https://books.google.com/books?id=aeAg1X7afOoC Dictionary of Minor Planet Names], Google books
* [http://obswww.unige.ch/~behrend/page_cou.html Asteroids and comets rotation curves, CdR] – Observatoire de Genève, Raoul Behrend
* [https://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center
* {{AstDys|164}}
* {{JPL small body}}

{{Minor planets navigator |163 Erigone |number=164 |165 Loreley}}
{{Small Solar System bodies}}
{{Authority control}}

{{DEFAULTSORT:000164}}
Category:Background asteroids
Eva
Eva
Category:CX-type asteroids (Tholen)
Category:X-type asteroids (SMASS)
18760712
Category:Objects observed by stellar occultation

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Adapted from the Wikipedia article [164 Eva](https://en.wikipedia.org/wiki/164_Eva) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/164_Eva?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.