588 Achilles

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588 Achilles
Discovery [1]
Discovered by M. Wolf
Discovery site Heidelberg Obs.
Discovery date 22 February 1906
MPC designation (588) Achilles
Pronunciation /əˈkɪlz/, ə-KIL-eez
Named after
Achilles (Greek mythology)[2]
1906 TG
Jupiter trojan[1][3]
(Greek camp)[4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 111.28 yr (40,646 days)
Aphelion 5.9712 AU
Perihelion 4.4463 AU
5.2087 AU
Eccentricity 0.1464
11.89 yr (4,342 days)
0° 4m 58.44s / day
Inclination 10.318°
Jupiter MOID 0.5701 AU
TJupiter 2.9460
Physical characteristics
Mean diameter
130.10±0.55 km[5]
133.22±3.33 km[6]
135.47±4.1 km (IRAS:15)[7]
7.0 h[8]
7.312±0.003 h[9]
7.32±0.02 h[10]
7.306 h[1]
7.306±0.002 h[11][12]
12 h[13]
0.0328±0.002 (IRAS:15)[1][7]
Tholen = DU [1][3]
B–V = 0.755[1]
U–B = 0.216[1]

588 Achilles, provisional designation 1906 TG, is a large and dark asteroid, classified as Jupiter trojan (L4 group), the first and 6th-largest of its kind ever confirmed by astronomers[14] (A904 RD was discovered 2 years previously, but was not observed long enough to calculate an orbit). It was discovered on 22 February 1906, by the German astronomer Max Wolf at Heidelberg Observatory in southern Germany, it measures about 133 kilometers (83 miles) in diameter and was named after Achilles from Greek mythology.[15]

Orbit and classification[edit]

Achilles orbits the Sun at a distance of 4.4–6.0 AU in the L4 Lagrangian point of the SunJupiter System once every 11 years and 10 months (4,337 days). Its orbit shows an eccentricity of 0.15 and an inclination of 10 degrees from the plane of the ecliptic.[1] The asteroid is the first known example of the stable solution of the three-body problem worked out by French mathematician Joseph Lagrange in 1772, after whom the minor planet 1006 Lagrangea is named. After the discovery of other asteroids with similar orbital characteristics, which were also named after heroes from the Trojan War (see below), the term "Trojan asteroids" or "Jupiter trojans" became commonly used;[2] in addition, a rule was established that the L4 point was the "Greek camp", whereas the L5 point was the "Trojan camp", though not before each camp had acquired a "spy" (624 Hektor in the Greek camp and 617 Patroclus in the Trojan camp).

Physical characteristics[edit]

Spectral type[edit]

In the Tholen taxonomic scheme, Achilles is classified as a D-type asteroid with an unusual spectrum (DU).[1]


Photometric observations of this asteroid during 1994 were used to build a light-curve showing a rotation period of 7.32±0.02 hours with a brightness variation of 0.31±0.01 magnitude.[10] This result is in good agreement with prior studies.[11][9]

Diameter and albedo[edit]

According to the surveys carried out by the Infrared Astronomical Satellite, IRAS, the Japanese Akari satellite, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the body's surface has a very low albedo in the range of 0.0328 to 0.043, making its absolute magnitude of approximately 8.57 correspond to a diameter of 130.1 to 135.5 kilometers.[7][6][5]

The largest Jupiter trojans
Trojan Diameter (km)
624 Hektor 225
617 Patroclus 140
911 Agamemnon 131
588 Achilles 130
3451 Mentor 126
3317 Paris 119
1867 Deiphobus 118
1172 Äneas 118
1437 Diomedes 118
1143 Odysseus 115
Source: JPL Small-Body Database, NEOWISE data


This minor planet's name was suggested by Austrian astronomer Johann Palisa, it was named after Achilles, the legendary hero from Greek mythology and central figure in Homer's Iliad which tells the accounts of the Trojan War (also see 5700 Homerus and 6604 Ilias). As an infant, Achilles was plunged in the River Styx by his mother Thetis (also see 17 Thetis), thus rendering his body invulnerable excepting the heel by which he was held. He slew Hector (see also 624 Hektor), the greatest Trojan warrior. He was eventually killed by an arrow in the heel by Paris (see 3317 Paris).[2]


  1. ^ a b c d e f g h i j k "JPL Small-Body Database Browser: 588 Achilles (1906 TG)" (2017-06-05 last obs.). Jet Propulsion Laboratory. Retrieved 19 October 2017. 
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (588) Achilles. Springer Berlin Heidelberg. p. 61. ISBN 978-3-540-00238-3. Retrieved 2 August 2016. 
  3. ^ a b "LCDB Data for (588) Achilles". Asteroid Lightcurve Database (LCDB). Retrieved 2 August 2016. 
  4. ^ "List of Jupiter Trojans". Minor Planet Center. 20 June 2016. Retrieved 2 August 2016. 
  5. ^ a b c d "WISE/NEOWISE Observations of the Jovian Trojan Population (Online Data Query) (NB. pad asteroid # to 5 digits with leading 0s)". Retrieved 18 August 2016. 
  6. ^ a b c d "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey (Online Data Query)". October 2011. Retrieved 18 August 2016. 
  7. ^ a b c d Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. Bibcode:2004PDSS...12.....T. Retrieved 1 January 2016. 
  8. ^ Angeli, C. A.; Lazzaro, D.; Florczak, M. A.; Betzler, A. S.; Carvano, J. M. (May 1999). "A contribution to the study of asteroids with longrotational period". Planetary and Space Science. 47 (5): 699–714. Bibcode:1999P&SS...47..699A. doi:10.1016/S0032-0633(98)00122-6. Retrieved 1 January 2016. 
  9. ^ a b Stephens, Robert D. (April 2010). "Trojan Asteroids Observed from GMARS and Santana Observatories: 2009 October - December". The Minor Planet Bulletin. 37 (2): 47–48. Bibcode:2010MPBu...37...47S. ISSN 1052-8091. Retrieved 1 January 2016. 
  10. ^ 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 2 August 2016. 
  11. ^ a b Shevchenko, V. G.; Krugly, Yu. N.; Belskaya, I. N.; Chiorny, V. G.; Gaftonyuk, N. M.; Slyusarev, I. G.; et al. (March 2009). "Do Trojan Asteroids Have the Brightness Opposition Effect?". 40th Lunar and Planetary Science Conference. Bibcode:2009LPI....40.1391S. Retrieved 1 January 2016. 
  12. ^ Shevchenko, V. G.; Belskaya, I. N.; Slyusarev, I. G.; Krugly, Yu. N.; Chiorny, V. G.; Gaftonyuk, N. M.; et al. (January 2012). "Opposition effect of Trojan asteroids". Icarus. 217 (1): 202–208. Bibcode:2012Icar..217..202S. doi:10.1016/j.icarus.2011.11.001. Retrieved 1 January 2016. 
  13. ^ Zappala, V.; di Martino, M.; Cellino, A.; de Sanctis, G.; Farinella, P. (December 1989). "Rotational properties of outer belt asteroids". Icarus: 354–368.ResearchsupportedbyCNRandMPI. Bibcode:1989Icar...82..354Z. doi:10.1016/0019-1035(89)90043-2. ISSN 0019-1035. Retrieved 1 January 2016. 
  14. ^ "JPL Small-Body Database Search Engine: orbital class (TJN) and diameter > 50 (km)". JPL's Solar System Dynamics Group. Retrieved 2012-03-28. 
  15. ^ "588 Achilles (1906 TG)". Minor Planet Center. Retrieved 2 August 2016. 

External links[edit]