3240 Laocoon

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3240 Laocoon
Discovery [1]
Discovered by E. F. Helin
S. J. Bus
Discovery site Palomar Obs.
Discovery date 7 November 1978
MPC designation (3240) Laocoon
Pronunciation /lˈɒk.ɒn/ lay-OK-oh-on
Named after
(Greek mythology)[2]
1978 VG6 · 1976 SA9
1976 SL2 · 1978 WS12
Jupiter trojan[3]
(Trojan camp)[4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 40.48 yr (14,786 days)
Aphelion 5.8988 AU
Perihelion 4.5727 AU
5.2357 AU
Eccentricity 0.1266
11.98 yr (4,376 days)
0° 4m 56.28s / day
Inclination 2.3348°
Jupiter MOID 0.3117 AU
Jupiter Tisserand parameter 2.9820
Physical characteristics
Dimensions 50.77 km (calculated)[5]
51.69±0.25 km[6]
51.695±0.252 km[7]
11.312±0.024 h[8]
0.057 (assumed)[5]
D[9] · C[5]
9.95±0.32[9] · 10.1[6] · 10.2[1][5]

3240 Laocoon (/lˈɒk.ɒn/ lay-OK-oh-on), provisional designation 1978 VG6, is a carbonaceous Jupiter trojan from the Trojan camp, approximately 51 kilometers in diameter. It was discovered on 7 November 1978, by American astronomers Eleanor Helin and Schelte Bus at Palomar Observatory in California.[3] It was named after Laocoön from Greek mythology.[2]

Classification and orbit[edit]

Laocoon resides in the Trojan camp of Jupiter's L5 Lagrangian point, which lies 60° behind the gas giant's orbit,[4] and orbits the Sun at a distance of 4.6–5.9 AU once every 11 years and 12 months (4,376 days). Its orbit has an eccentricity of 0.13 and an inclination of 2° with respect to the ecliptic.[1] The first observation was made at Crimea–Nauchnij in 1976, extending the asteroid's observation arc by 2 years prior to its discovery.[3]

Physical characteristics[edit]

The C-type asteroid is also characterized as a D-type by Pan-STARRS' large-scale photometric survey.[9]


In April 1996, Laocoon was observed by Italian astronomer Stefano Mottola using the now decommissioned Bochum 0.61-metre Telescope at ESO's La Silla Observatory in Chile. The lightcurve gave a rotation period of 11.312±0.024 hours with a brightness variation of 0.55±0.02 in magnitude (U=2+).[8]

Diameter and albedo[edit]

According to the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the Jovian asteroid measures 51.7 kilometers in diameter and its surface has an albedo of 0.060,[6][7] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 50.8 kilometers with an absolute magnitude of 10.2.[5]


This minor planet was named after the Troyan priest Laocoön from Greek mythology. He and both his sons were killed by serpents sent by the gods because he tried to expose the Greek's deception of the Trojan Horse.[2] The official naming citation was published by the Minor Planet Center on 7 September 1987 (M.P.C. 12210).[10]

See also[edit]


  1. ^ a b c d "JPL Small-Body Database Browser: 3240 Laocoon (1978 VG6)" (2017-03-19 last obs.). Jet Propulsion Laboratory. Retrieved 17 June 2017. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (3240) Laocoon. Springer Berlin Heidelberg. p. 269. ISBN 978-3-540-00238-3. Retrieved 26 September 2016. 
  3. ^ a b c "3240 Laocoon (1978 VG6)". Minor Planet Center. Retrieved 26 September 2016. 
  4. ^ a b "List of Jupiter Trojans". Minor Planet Center. 20 August 2016. Retrieved 26 September 2016. 
  5. ^ a b c d e "LCDB Data for (3240) Laocoon". Asteroid Lightcurve Database (LCDB). Retrieved 26 September 2016. 
  6. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results" (PDF). The Astrophysical Journal. 741 (2): 25. Bibcode:2011ApJ...741...90M. arXiv:1109.6407Freely accessible. doi:10.1088/0004-637X/741/2/90. Retrieved 26 September 2016. 
  7. ^ a b c Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R. (November 2012). "WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy". The Astrophysical Journal. 759 (1): 10. Bibcode:2012ApJ...759...49G. arXiv:1209.1549Freely accessible. doi:10.1088/0004-637X/759/1/49. Retrieved 26 September 2016. 
  8. ^ a b Mottola, Stefano; Di Martino, Mario; Erikson, Anders; Gonano-Beurer, Maria; Carbognani, Albino; Carsenty, Uri; et al. (May 2011). "Rotational Properties of Jupiter Trojans. I. Light Curves of 80 Objects". The Astronomical Journal. 141 (5): 32. Bibcode:2011AJ....141..170M. doi:10.1088/0004-6256/141/5/170. Retrieved 26 September 2016. 
  9. ^ a b c Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. Bibcode:2015Icar..261...34V. arXiv:1506.00762Freely accessible. doi:10.1016/j.icarus.2015.08.007. Retrieved 26 September 2016. 
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 26 September 2016. 

External links[edit]