11552 Boucolion/baʊˈkoʊliɒn/ is aJupiter trojan from theTrojan camp, approximately 53 kilometers (33 miles) in diameter. It was discovered on 27 January 1993, by Belgian astronomerEric Elst at theCERGA Observatory in Caussols, France.^[1] The darkD-type asteroid is one of the90 largest Jupiter trojans and has a longrotation period of 32.4 hours.^[11] It was named from Greek mythology after theBoucolion, who lost his sons in theTrojan War.^[1]

Boucolion is a darkJupiter trojan in a 1:1orbital resonance with Jupiter. It is located in the traileringTrojan camp at the Gas Giant'sL₅Lagrangian point, 60° behind its orbit(seeTrojans in astronomy).^[4] It is also a non-family asteroid of theJovian background population.^[5] It orbits the Sun at a distance of 4.5–6.1 AU once every 12 years and 1 month (4,418 days;semi-major axis of 5.27 AU). Its orbit has aneccentricity of 0.15 and aninclination of 15° with respect to theecliptic.^[3]

The asteroid was first observed as1975 NP₁ atCrimea–Nauchnij in July 1973. The body'sobservation arc begins with its official discovery observation at Caussols in January 1993.^[1]

In theSDSS-based taxonomy,Boucolion is aD-type asteroid,^[10][12] the most common type among the larger Jupiter trojans. It has also been characterized as a D-type byPan-STARRS' survey, while theCollaborative Asteroid Lightcurve Link assumes it to be a carbonaceousC-type asteroid.^[9][11]

In September 2012, a rotationallightcurve ofBoucolion was first obtained fromphotometric observations by astronomers at thePalomar Transient Factory (PTF) in California. Lightcurve analysis gave arotation period of 16.150 and 16.177 hours with a brightness amplitude of 0.23 and 0.25magnitude in the R- and S-band, respectively (U=2/2).^[11][13]

A more refined, alternative period solution of32.44±0.05 hours with an amplitude of 0.21 magnitude was measured byRobert Stephens at theCenter for Solar System Studies in January 2015 (U=2).^[8][a] The result seems to be a 1:2 alias, i.e. twice the period, of the previously obtained lightcurve at the PTF. While not being aslow rotator,Boucolion has one of the longest periods among the larger Jupiter trojans(see table below).^[11]

According to the surveys carried out by the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Boucolion measures 51.136 and 53.91 kilometers in diameter and its surface has analbedo of 0.062 and 0.035, respectively.^[6][7] CALL assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 53.16 kilometers based on anabsolute magnitude of 10.1.^[11]

Thisminor planet was named fromGreek mythology afterBoucolion, father of the two Trojan warriorsPedasos andAesopos, who both were slain near theRiver Scamander during theTrojan War. The official naming citation was published by theMinor Planet Center on 6 January 2003 (M.P.C. 47299).^[14]

• Asteroid Lightcurve Database (LCDB), query form (infoArchived 16 December 2017 at theWayback Machine)
• Dictionary of Minor Planet Names, Google books
• Discovery Circumstances: Numbered Minor Planets (10001)-(15000) – Minor Planet Center
• 11552 Boucolion atAstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 11552 Boucolion at theJPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Jupiter trojans (Trojan camp)
• Discoveries by Eric Walter Elst
• Named minor planets
• Astronomical objects discovered in 1993

• Use dmy dates from June 2018
• Webarchive template wayback links
• JPL Small-Body Database ID different from Wikidata