15440 Eioneus
{{Short description|Jupiter trojan from the Greek camp}}
{{Use dmy dates|date=June 2018}}
{{Infobox planet
| minorplanet = yes
| name = 15440 Eioneus
| background = #C2FFFF
| image =
| image_size =
| caption =
| discoverer = CSS
| discovery_site = Catalina Stn.
| discovered = 19 November 1998
| mpc_name = (15440) Eioneus
| alt_names = {{mp|1998 WX|4}}{{·}}1992 LD
| adjective = Eione(i)an
| pronounced =
| named_after = Eioneus
{{small|(Greek mythology)}}
| mp_category = Jupiter trojan
{{nowrap|Greek{{·}}background}}
| epoch = 23 March 2018 (JD 2458200.5)
| uncertainty = 0
| observation_arc = 66.48 yr (24,280 d)
| aphelion = 5.4151 AU
| perihelion = 5.1821 AU
| semimajor = 5.2986 AU
| eccentricity = 0.0220
| period = 12.20 yr (4,455 d)
| mean_anomaly = 240.92°
| mean_motion = {{Deg2DMS|0.0808|sup=ms}} / day
| inclination = 28.743°
| asc_node = 120.55°
| arg_peri = 279.64°
| jupiter_moid = 0.0063 AU
| tisserand = 2.7510
| mean_diameter = {{val|62.52|0.83|u=km}}
{{val|66.48|3.8|u=km}}
{{val|71.88|3.87|u=km}}
| rotation = {{val|21.43|0.02|ul=h}}{{efn|name=lightcurve-plots-Stephens}}
| albedo = {{val|0.072|0.011}}
{{val|0.079|0.009}}
{{val|0.0916|0.011}}
| spectral_type = C {{small|(assumed)}}
V–I {{=}} {{val|0.970|0.041}}
| abs_magnitude = 9.10
9.5
9.6
{{val|9.68|0.31}}
}}
15440 Eioneus, provisional designation: {{mp|1998 WX|4}}, is a dark Jupiter trojan from the Greek camp, approximately {{convert|66|km|mi|abbr=off|sigfig=2|sp=us}} in diameter. It was discovered on 19 November 1998, by astronomers with the Catalina Sky Survey at the Catalina Station near Tucson, Arizona, in the United States. The assumed C-type asteroid belongs to the 60 largest Jupiter trojans. It has a rotation period of 21.43 hours and possibly a spherical shape. It was named from Greek mythology after Eioneus who was killed by Hector.
Orbit and classification
Eioneus is a dark Jovian asteroid orbiting in the leading Greek camp at Jupiter's {{L4}} Lagrangian point, 60° ahead of the Gas Giant's orbit in a 1:1 resonance {{crossreference|(see Trojans in astronomy)}}. It is also a non-family asteroid in the Jovian background population.
It orbits the Sun at a distance of 5.2–5.4 AU once every 12 years and 2 months (4,455 days; semi-major axis of 5.3 AU). Its orbit has an eccentricity of 0.02 and an inclination of 29° with respect to the ecliptic. The body's observation arc begins with a precovery published by the Digitized Sky Survey and taken at the Palomar Observatory in November 1951, or 47 years prior to its official discovery observation at Catalina.
Naming
This minor planet was numbered on 21 June 2000 ({{small|M.P.C. 40826}}). On 14 May 2021, the object was named from Greek mythology by the Working Group for Small Bodies Nomenclature (WGSBN), after the Greek warrior Eioneus who was killed by a spear from Hector during the Trojan War.
Physical characteristics
Eioneus is an assumed C-type asteroid, while the majority of large Jupiter trojans are D-types. It has a typical V–I color index of 0.97.
= Rotation period =
Since January 2013, a large number of a rotational lightcurve of Eioneus have been obtained from photometric observations by Robert Stephens at the Center for Solar System Studies in California.{{efn|name=lightcurve-plots-Stephens}} Analysis of the best-rated lightcurve from June 2017 gave a longer-than-average rotation period of {{val|21.43|0.02|ul=h}} hours with a low brightness amplitude of {{val|0.09|0.02}} magnitude ({{small|U=2+}}), indicative of a rather spherical shape.
= Diameter and albedo =
According to the surveys carried out by the Japanese Akari satellite, the Infrared Astronomical Satellite IRAS and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Eioneus measures between 62.52 and 71.88 kilometers in diameter and its surface has an albedo between 0.072 and 0.092. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0585 and a diameter of 66.04 kilometers based on an absolute magnitude of 9.6.
{{Largest Jupiter trojans}}
Notes
{{notelist|refs=
{{efn|name=lightcurve-plots-Stephens|1=Lightcurve plots of (15440) 1998 WX4 from [http://www.planetarysciences.org/plots/RDS/15440_1998WX4_2013-01-05.PNG 2013], [http://www.planetarysciences.org/plots/RDS/15440_1998WX4_2014-03-07.PNG 2014], [http://www.planetarysciences.org/plots/RDS/15440_1998WX4_2015-03-29.PNG 2015], [http://www.planetarysciences.org/plots/RDS/15440_1998WX4_20160529.PNG 2016] and [http://www.planetarysciences.org/plots/RDS/15440_1998WX4_20170601.PNG 2017] by Robert Stephens at the Center for Solar System Studies {{Obscode|U81}}. Quality code is n.a/n.a/2+/3-/3-. (lightcurve rating at CS3). Summary figures at the [http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=15440%7C1998+WX4 LCDB] and [http://www.planetarysciences.org/PHP/CS3_Lightcurves.php CS3].}}
}}
References
{{reflist|30em|refs=
|type = 2018-05-20 last obs.
|title = JPL Small-Body Database Browser: 15440 (1998 WX4)
|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2015440
|publisher = Jet Propulsion Laboratory
|accessdate = 14 June 2018}}
|title = List of Jupiter Trojans
|work = Minor Planet Center
|date = 30 May 2018
|url = https://www.minorplanetcenter.net/iau/lists/JupiterTrojans.html
|accessdate = 14 June 2018}}
|title = 15440 (1998 WX4)
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=15440
|accessdate = 14 June 2018}}
|title = MPC/MPO/MPS Archive
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html
|accessdate = 14 June 2018}}
|title = WGSBN Bulletin Archive
|work = Working Group for Small Bodies Nomenclature
|date = 14 May 2021
|url = https://www.wgsbn-iau.org/files/Bulletins/index.html
|accessdate = 16 May 2021}} ([https://www.wgsbn-iau.org/files/Bulletins/V001/WGSBNBull_V001_001.pdf Bulletin #1])
|first1 = T. |last1 = Grav
|first2 = A. K. |last2 = Mainzer
|first3 = J. M. |last3 = Bauer
|first4 = J. R. |last4 = Masiero
|first5 = C. R. |last5 = Nugent
|date = November 2012
|title = WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy
|journal = The Astrophysical Journal
|volume = 759
|issue = 1
|page = 10
|bibcode = 2012ApJ...759...49G
|doi = 10.1088/0004-637X/759/1/49
|arxiv = 1209.1549
|s2cid = 119101711
}} ([http://vizier.cfa.harvard.edu/viz-bin/VizieR-6?-source=J/ApJ/759/49/table1&MPC=15440 online catalog])
|title = Asteroid (15440) 1998 WX4 – Proper elements
|publisher = AstDyS-2, Asteroids – Dynamic Site
|url = https://newton.spacedys.com/astdys/index.php?n=15440&pc=1.1.6
|accessdate = 5 June 2018}}
|title = Asteroid (15440) 1998 WX4
|work = Small Bodies Data Ferret
|url = https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=15440
|accessdate = 14 June 2018
|archive-date = 14 June 2018
|archive-url = https://web.archive.org/web/20180614171853/https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=15440
|url-status = dead
}}
|first1 = E. F. |last1 = Tedesco
|first2 = P. V. |last2 = Noah
|first3 = M. |last3 = Noah
|first4 = S. D. |last4 = Price
|date = October 2004
|title = IRAS Minor Planet Survey V6.0
|url = https://sbnarchive.psi.edu/pds3/iras/IRAS_A_FPA_3_RDR_IMPS_V6_0/data/diamalb.tab
|journal = NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0
|volume = 12
|pages = IRAS-A-FPA-3-RDR-IMPS-V6.0
|bibcode = 2004PDSS...12.....T
|accessdate = 15 June 2018}}
|title = LCDB Data for (15440)
|publisher = Asteroid Lightcurve Database (LCDB)
|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=15440%7C
|accessdate = 14 June 2018}}
|display-authors = 6
|first1 = Fumihiko |last1 = Usui
|first2 = Daisuke |last2 = Kuroda
|first3 = Thomas G. |last3 = Müller
|first4 = Sunao |last4 = Hasegawa
|first5 = Masateru |last5 = Ishiguro
|first6 = Takafumi |last6 = Ootsubo
|first7 = Daisuke |last7 = Ishihara
|first8 = Hirokazu |last8 = Kataza
|first9 = Satoshi |last9 = Takita
|first10 = Shinki |last10 = Oyabu
|first11 = Munetaka |last11 = Ueno
|first12 = Hideo |last12 = Matsuhara
|first13 = Takashi |last13 = Onaka
|date = October 2011
|title = Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey
|journal = Publications of the Astronomical Society of Japan
|volume = 63
|issue = 5
|pages = 1117–1138
|bibcode = 2011PASJ...63.1117U
|doi = 10.1093/pasj/63.5.1117
|doi-access=
}} ([http://vizier.cfa.harvard.edu/viz-bin/VizieR-5?-source=J/PASJ/63/1117/acua_v1&Num=15440 online], [https://core.ac.uk/download/pdf/43545172.pdf AcuA catalog p. 153])
|first1 = Robert D. |last1 = Stephens
|first2 = Brian D. |last2 = Warner
|date = October 2017
|title = Lightcurve Analysis of L4 Trojan Asteroids at the Center for Solar System Studies 2017 April-June
|journal = The Minor Planet Bulletin
|volume = 44
|issue = 4
|pages = 312–316
|issn = 1052-8091
|bibcode = 2017MPBu...44..312S}}
|first1 = Robert D. |last1 = Stephens
|first2 = Daniel R. |last2 = Coley
|first3 = Brian D. |last3 = Warner
|first4 = Linda, M. |last4 = French
|date = October 2016
|title = Lightcurves of Jovian Trojan Asteroids from the Center for Solar System Studies: L4 Greek Camp and Spies
|journal = The Minor Planet Bulletin
|volume = 43
|issue = 4
|pages = 323–331
|issn = 1052-8091
|bibcode = 2016MPBu...43..323S}}
|first1 = Robert D. |last1 = Stephens
|first2 = Daniel, R. |last2 = Coley
|first3 = Linda M. |last3 = French
|date = January 2016
|title = Large L5 Jovian Trojan Asteroid Lightcurves from the Center for Solar System Studies
|journal = The Minor Planet Bulletin
|volume = 43
|issue = 1
|pages = 15–22
|issn = 1052-8091
|bibcode = 2016MPBu...43...15S}}
|display-authors = 6
|first1 = Peter |last1 = Veres
|first2 = Robert |last2 = Jedicke
|first3 = Alan |last3 = Fitzsimmons
|first4 = Larry |last4 = Denneau
|first5 = Mikael |last5 = Granvik
|first6 = Bryce |last6 = Bolin
|first7 = Serge |last7 = Chastel
|first8 = Richard J. |last8 = Wainscoat
|first9 = William S. |last9 = Burgett
|first10 = Kenneth C. |last10 = Chambers
|first11 = Heather |last11 = Flewelling
|first12 = Nick |last12 = Kaiser
|first13 = Eugen A. |last13 = Magnier
|first14 = Jeff S. |last14 = Morgan
|first15 = Paul A. |last15 = Price
|first16 = John L. |last16 = Tonry
|first17 = Christopher |last17 = Waters
|date = November 2015
|title = Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results
|journal = Icarus
|volume = 261
|pages = 34–47
|bibcode = 2015Icar..261...34V
|doi = 10.1016/j.icarus.2015.08.007
|arxiv = 1506.00762|s2cid = 53493339 }}
}}
External links
- [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://www.minorplanetcenter.net/iau/lists/NumberedMPs015001.html Discovery Circumstances: Numbered Minor Planets (15001)-(20000)] – Minor Planet Center
- {{AstDys|15440}}
- {{JPL small body|id=2015440}}
{{Minor planets navigator | |number=15440 | }}
{{Small Solar System bodies}}
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