{{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 | discovery_site=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 | orbit_ref=<ref name="JPL"/> | epoch=31 July 2016 (JD 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 (1561.2 d) | inclination=24.4564° | asc_node=76.8519° | arg_peri=283.9561° | mean_anomaly=219.5472° | 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 | 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 asteroid that was discovered by the French brothers Paul Henry and Prosper Henry on July 12, 1876, in Paris. The reason the name Eva was chosen remains unknown, though Karl Ludwig Littrow suspected a "worldly origin" (''"Mit dem Namen könnten wir wie bei 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 for 164 Eva were published in 1877 by American astronomer Winslow Upton.<ref name="Upton1877"/>
This asteroid is categorized as a C-type asteroid and is probably composed of primitive carbonaceous chondritic materials. Dust activity due to sublimation has been detected on this asteroid, suggesting the presence of water ice in its interior.<ref name=Busarev_et_al_2024/>
This object has an estimated diameter of around {{Val|105|u=km}}. Photometric observations of this asteroid at the Palmer Divide Observatory in Colorado Springs, Colorado, during 2008 gave a light curve with a period of 13.672 ± 0.003 hours and a small brightness variation of 0.04 ± 0.01 in magnitude. 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 fourteen stars.{{cn|date=March 2026}}
164 Eva is orbiting the Sun at a distance of {{Val|2.63|u=km}} with an eccentricity of 0.35 and an orbital period of 4.27 years. The orbital plane is inclined at an angle of 24.5° to the 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. 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'' (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