{{Short description|Near-Earth asteroid}} {{Use dmy dates|date=September 2020}} {{Infobox planet | minorplanet = yes | name = 4341 Poseidon | background = #FFC2E0 | image = | image_size = | caption = | discovery_ref = <ref name="jpldata" /> | discovered = 29 May 1987 | discoverer = C. Shoemaker | discovery_site = Palomar Obs. | mpc_name = (4341) Poseidon | alt_names = 1987 KF | pronounced = | named_after = Poseidon<br />{{small|(Greek mythology)}}<ref name="springer" /> | mp_category = Apollo{{·}}NEO | orbit_ref = <ref name="jpldata" /> | epoch = 4 September 2017 (JD 2458000.5) | uncertainty = 0 | observation_arc = 30.05 yr (10,975 days) | aphelion = 3.0819 AU | perihelion = 0.5881 AU | semimajor = 1.8350 AU | eccentricity = 0.6795 | period = 2.49 yr (908 days) | mean_anomaly = 93.192° | mean_motion = {{Deg2DMS|0.3965|sup=ms}} / day | inclination = 11.852° | asc_node = 108.11° | arg_peri = 15.652° | moid = 0.1941 AU{{·}}75.6 LD | mean_diameter = {{val|2.32|ul=km}} {{small|(derived)}}<ref name="lcdb" /> | rotation = {{val|6.262|ul=h}}<ref name="Pravec-1998b" /><br />{{val|6.2656|}} h<ref name="Krugly-2002a" /> | albedo = 0.18 {{small|(assumed)}}<ref name="lcdb" /> | spectral_type = SMASS {{=}} O<ref name="jpldata" /><ref name="lcdb" /> | abs_magnitude = 15.65<ref name="lcdb" /><ref name="Krugly-2002a" />{{·}}16.0<ref name="jpldata" />{{·}}{{val|16.11|0.80}}<ref name="Veres-2015" /> }}
'''4341 Poseidon''' (''prov. designation:'' {{mp|1987 KF}}) is a rare-type asteroid classified as near-Earth object of the Apollo group, approximately {{convert|2.3|km|mi|abbr=off|sp=us}} in diameter. It was discovered by American astronomer Carolyn Shoemaker at Palomar Observatory on 29 May 1987.<ref name="MPC-Poseidon" /> The asteroid was named after Poseidon from Greek mythology.<ref name="springer" />
== Orbit and classification ==
''Poseidon'' orbits the Sun at a distance of 0.6–3.1 AU once every 2 years and 6 months (908 days). Its orbit has an eccentricity of 0.68 and an inclination of 12° with respect to the ecliptic.<ref name="jpldata" />
As no precoveries were taken, the asteroid's observation arc begins with its discovery in 1987.<ref name="MPC-Poseidon" /> ''Poseidon'' may be associated with the Taurid Complex of meteor showers.<ref name="Babadzhanov-2001"/> It has an Earth minimum orbital intersection distance of {{convert |0.1941 |AU |km |abbr=on |lk=off |sigfig=3}}, which corresponds to 75.6 lunar distances.<ref name="jpldata" />
== Naming ==
This minor planet was named for the "God of the Sea", Poseidon, one of the Twelve Olympians in Greek mythology. He was also referred to as "Earth-Shaker" due to his role in provoking earthquakes, which were then thought to be caused by ocean waves beating on the shore. He was the brother of Zeus ''(see 5731 Zeus)'', and an enemy of the Trojans in the Trojan War.<ref name="springer" /> The {{MoMP|4341|naming citation}} was published by the Minor Planet Center on 30 January 1991 ({{small|M.P.C. 17656}}).<ref name="MPC-Circulars-Archive" />
== Physical characteristics ==
In the SMASS classification, ''Poseidon'' is an O-type asteroid.<ref name="jpldata" />
=== Diameter and albedo ===
The ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.18 and derives a diameter of 2.32 kilometers with an absolute magnitude of 15.65.<ref name="lcdb" /> As of 2017, no other estimates for its diameter and albedo have been published.<ref name="jpldata" /><ref name="lcdb" />
=== Lightcurves ===
In 1998, a rotational lightcurve of ''Poseidon'' was published from photometric observations made by Czech astronomer Petr Pravec at Ondřejov Observatory. It gave a period of {{val|6.262|}} hours with a brightness variation of 0.08 magnitude ({{small|U=2}}).<ref name="Pravec-1998b" />
A second lightcurve was obtained during the '' Near-Earth Objects Follow-up Program'' which gave a concurring period of {{val|6.2656|}} hours and an amplitude of 0.07 magnitude ({{small|U=2}}).<ref name="Krugly-2002a" /> A low brightness variation typically indicates that the body has a nearly spheroidal shape.
== References == {{reflist|30em|refs=
<ref name="Babadzhanov-2001">{{cite journal |last1 = Babadzhanov |first1=P. B. |title = Search for meteor showers associated with Near-Earth Asteroids |journal = Astronomy and Astrophysics |volume = 373 |issue = 1 |pages = 329–335 |date = 2001 |doi = 10.1051/0004-6361:20010583 |bibcode = 2001A&A...373..329B |doi-access= free }}</ref>
<ref name="jpldata">{{cite web |type = 2017-06-15 last obs. |title = JPL Small-Body Database Browser: 4341 Poseidon (1987 KF) |url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004341 |publisher = Jet Propulsion Laboratory |access-date = 20 June 2017}}</ref>
<ref name="springer">{{cite book |title = Dictionary of Minor Planet Names – (4341) Poseidon |last = Schmadel | first = Lutz D. |publisher = Springer Berlin Heidelberg |chapter = (4341) Poseidon |page = 372 |date = 2007 |isbn = 978-3-540-00238-3 |doi = 10.1007/978-3-540-29925-7_4293}}</ref>
<ref name="MPC-Poseidon">{{cite web |title = 4341 Poseidon (1987 KF) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=4341 |access-date = 27 October 2016}}</ref>
<ref name="MPC-Circulars-Archive">{{cite web |title = MPC/MPO/MPS Archive |work = Minor Planet Center |url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html |access-date = 27 October 2016}}</ref>
<ref name="lcdb">{{cite LCDB|number = 4341 |access-date = 27 October 2016}}</ref>
<ref name="Pravec-1998b">{{Cite journal |first1 = Petr |last1 = Pravec |first2 = Marek |last2 = Wolf |first3 = Lenka |last3 = Sarounová |date = November 1998 |title = Lightcurves of 26 Near-Earth Asteroids |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=1998Icar..136..124P |journal = Icarus |volume = 136 |issue = 1 |pages = 124–153 |bibcode = 1998Icar..136..124P |doi = 10.1006/icar.1998.5993 |access-date= 27 October 2016}}</ref>
<ref name="Krugly-2002a">{{Cite journal |display-authors = 6 |first1 = Yu. N. |last1 = Krugly |first2 = I. N. |last2 = Belskaya |first3 = V. G. |last3 = Shevchenko |first4 = V. G. |last4 = Chiorny |first5 = F. P. |last5 = Velichko |first6 = S. |last6 = Mottola |first7 = A. |last7 = Erikson |first8 = G. |last8 = Hahn |first9 = A. |last9 = Nathues |first10 = G. |last10 = Neukum |first11 = N. M. |last11 = Gaftonyuk |first12 = E. |last12 = Dotto |date = August 2002 |title = The Near-Earth Objects Follow-up Program. IV. CCD Photometry in 1996-1999 |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2002Icar..158..294K |journal = Icarus |volume = 158 |issue = 2 |pages = 294–304 |bibcode = 2002Icar..158..294K |doi = 10.1006/icar.2002.6884 |access-date= 27 October 2016}}</ref>
<ref name="Veres-2015">{{cite journal |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 |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V |journal = Icarus |volume = 261 |pages = 34–47 |bibcode = 2015Icar..261...34V |doi = 10.1016/j.icarus.2015.08.007 |arxiv = 1506.00762 |access-date= 27 October 2016}}</ref>
}} <!-- end of reflist -->
== 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://books.google.com/books?id=aeAg1X7afOoC&pg 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 * {{NeoDys|4341}} * {{ESA-SSA|4341|Poseidon}} * {{JPL small body|id=2004341}}
{{Minor planets navigator|4340 Dence |number=4341 |4342 Freud}} {{Small Solar System bodies}} {{Authority control}}
{{DEFAULTSORT:Poseidon}} 004341 Category:Discoveries by Carolyn S. Shoemaker Category:Named minor planets 004341 19870529