11887 Echemmon
{{Use dmy dates|date=July 2018}}
{{Infobox planet
| minorplanet = yes
| name = 11887 Echemmon
| background = #C2FFFF
| image =
| image_size =
| caption =
| discoverer = F. Börngen
L. D. Schmadel
| discovery_site = Karl Schwarzschild Obs.
| discovered = 14 October 1990
| mpc_name = (11887) Echemmon
| alt_names = {{mp|1990 TV|12}}{{·}}{{mp|1989 SX|13}}
| pronounced = {{IPAc-en|ᵻ|ˈ|k|ɛ|m|ɒ|n}}
| named_after = Ἐχέμμων Echemmōn
{{small|(Greek mythology)}}
| mp_category = Jupiter trojan
{{nowrap|Trojan{{·}}background}}
| epoch = 23 March 2018 (JD 2458200.5)
| uncertainty = 0
| observation_arc = 63.26 yr (23,105 d)
| aphelion = 5.6556 AU
| perihelion = 4.7089 AU
| semimajor = 5.1823 AU
| eccentricity = 0.0913
| period = 11.80 yr (4,309 d)
| mean_anomaly = 171.52°
| mean_motion = {{Deg2DMS|0.0835|sup=ms}} / day
| inclination = 24.044°
| asc_node = 242.65°
| arg_peri = 112.06°
| jupiter_moid = 0.0514 AU
| tisserand = 2.8190
| mean_diameter = {{val|31.19|0.49|ul=km}}
{{val|38.51|u=km}} {{small|(calculated)}}
| rotation = {{val|8.47|0.01|ul=h}}{{efn|name=lightcurve-plots-CS3}}
| albedo = {{val|0.057}} {{small|(assumed)}}
{{val|0.095|0.008}}
| spectral_type = C {{small|(assumed)}}
}}
11887 Echemmon {{IPAc-en|ᵻ|ˈ|k|ɛ|m|ɒ|n}} is a Jupiter trojan from the Trojan camp, approximately {{convert|31|km|mi|abbr=off|sigfig=2|sp=us}} in diameter. It was discovered on 14 October 1990, by German astronomers Freimut Börngen and Lutz Schmadel at the Karl Schwarzschild Observatory in Tautenburg, Germany. The dark Jovian asteroid has a rotation period of 8.5 hours. It was named after the Trojan hero Echemmon from Greek mythology.
Orbit and classification
As all Jupiter trojans, Echemmon is in a 1:1 orbital resonance with Jupiter. It is located in the trailering Trojan camp at the Gas Giant's {{L5}} Lagrangian point, 60° behind its orbit {{crossreference|(see Trojans in astronomy)}}. It is also a non-family asteroid of the Jovian background population.
It orbits the Sun at a distance of 4.7–5.7 AU once every 11 years and 10 months (4,309 days; semi-major axis of 5.18 AU). Its orbit has an eccentricity of 0.09 and an inclination of 24° with respect to the ecliptic.
The body's observation arc begins with a precovery taken at the Palomar Observatory in November 1954, nearly 36 years prior to its official discovery observation at Tautenburg.
Naming
This minor planet was named from Greek mythology after the Trojan prince Echemmon, one of the many sons of King Priam of Troy. He was slain together with his brother Chromius by Diomedes, king of Argos, during the Trojan War. The name was suggested by the first discoverer, Freimut Börngen, and published by the Minor Planet Center on 9 March 2001 ({{small|M.P.C. 42361}}).
Physical characteristics
Echemmon is an assumed C-type asteroid, while most larger Jupiter trojans are D-types.
= Rotation period =
In November 2013, a rotational lightcurve of Echemmon was obtained over three nights of photometric observations by Robert Stephens at the Center for Solar System Studies in Landers, California. Lightcurve analysis gave a rotation period of {{val|8.47|0.01}} hours with a brightness amplitude of 0.15 magnitude ({{small|U=2}}).{{efn|name=lightcurve-plots-CS3}}
= Diameter and albedo =
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Echemmon measures 31.19 kilometers in diameter and its surface has an albedo of 0.095, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 38.51 kilometers based on an absolute magnitude of 10.8.
Notes
{{notelist|refs=
{{efn|name=lightcurve-plots-CS3|1=Lightcurve plots of (11887) Echemmon from [http://www.planetarysciences.org/plots/RDS/11887_ECHEMMON_2013-11-06.PNG Nov 2013] by Robert Stephens at the Center for Solar System Studies {{Obscode|U81}}. Quality code is 2- (lightcurve rating at CS3). Summary figures at the [http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=11887%7CEchemmon LCDB] and [http://www.planetarysciences.org/PHP/CS3_Lightcurves.php CS3].}}
}}
References
{{reflist|30em|refs=
|type = 2018-02-25 last obs.
|title = JPL Small-Body Database Browser: 11887 Echemmon (1990 TV12)
|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2011887
|publisher = Jet Propulsion Laboratory
|accessdate = 4 July 2018}}
|title = 11887 Echemmon (1990 TV12)
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=11887
|accessdate = 4 July 2018}}
|title = List of Jupiter Trojans
|work = Minor Planet Center
|first3 = V. |last3 = Carruba
|date = 1 July 2018
|url = https://www.minorplanetcenter.net/iau/lists/JupiterTrojans.html
|accessdate = 4 July 2018}}
|title = MPC/MPO/MPS Archive
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html
|accessdate = 4 July 2018}}
|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
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012ApJ...759...49G
|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
|access-date= 4 July 2018}} ([http://vizier.cfa.harvard.edu/viz-bin/VizieR-6?-source=J/ApJ/759/49/table1&MPC=11887 online catalog])
|title = Asteroid (11887) Echemmon – Proper Elements
|publisher = AstDyS-2, Asteroids – Dynamic Site
|url = https://newton.spacedys.com/astdys/index.php?n=11887&pc=1.1.6
|access-date= 4 July 2018}}
|title = LCDB Data for (11887) Echemmon
|publisher = Asteroid Lightcurve Database (LCDB)
|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=11887%7CEchemmon
|accessdate = 4 July 2018}}
|first1 = Robert D. |last1 = Stephens
|first2 = Linda M. |last2 = French
|first3 = Chelsea |last3 = Davitt
|first4 = Daniel R. |last4 = Coley
|date = April 2014
|title = At the Scaean Gates: Observations Jovian Trojan Asteroids, July- December 2013
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014MPBu...41...95S
|journal = The Minor Planet Bulletin
|volume = 41
|issue = 2
|pages = 95–100
|issn = 1052-8091
|bibcode = 2014MPBu...41...95S
|access-date= 4 July 2018}}
}}
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
- [https://www.minorplanetcenter.net/iau/lists/NumberedMPs010001.html Discovery Circumstances: Numbered Minor Planets (10001)-(15000)] – Minor Planet Center
- [https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=11887+Echemmon Asteroid 11887 Echemmon] {{Webarchive|url=https://web.archive.org/web/20180705004249/https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=11887+Echemmon |date=5 July 2018 }} at the Small Bodies Data Ferret
- {{AstDys|11887}}
- {{JPL small body|id=2011887}}
{{Minor planets navigator |11886 Kraske |number=11887 |(11888) 1990 UD3 }}
{{Small Solar System bodies}}
{{Authority control}}
{{DEFAULTSORT:Echemmon}}
Category:Discoveries by Freimut Börngen