1404 Ajax

Modelled shape of Ajax from its lightcurve
Discovery[1]
Discovered by	K. Reinmuth
Discovery site	Heidelberg Obs.
Discovery date	17 August 1936
Designations
MPC designation	(1404) Ajax
Pronunciation	/ˈeɪdʒæks/[2]
Named after	Ajax (Greek mythology)[3]
Alternative designations	1936 QW
Minor planet category	Jupiter trojan[1][4][5] Greek[6][7] · background[7]
Adjectives	Ajantian /əˈdʒæntiən/
Orbital characteristics[4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	81.76 yr (29,864 d)
Aphelion	5.9044 AU
Perihelion	4.6992 AU
Semi-major axis	5.3018 AU
Eccentricity	0.1137
Orbital period (sidereal)	12.21 yr (4,459 d)
Mean anomaly	247.16°
Mean motion	0° 4m 50.52s / day
Inclination	18.005°
Longitude of ascending node	332.92°
Argument of perihelion	59.772°
Jupiter MOID	0.0433 AU
TJupiter	2.8890
Physical characteristics
Mean diameter	81.43 km (derived)[5] 81.69±3.2 km[8] 83.99±1.28 km[9] 96.34±2.25 km[10]
Synodic rotation period	28.4 h[11] 29.38±0.01 h[12] 34 h[13]
Geometric albedo	0.048±0.009[9] 0.050±0.003[10] 0.0508 (derived)[5] 0.0665±0.005[8]
Spectral type	C (assumed)[5] V–I = 0.960±0.032[5]
Absolute magnitude (H)	9.00[8][10] 9.3[1][4][5][9] 9.87±0.47[14]

1404 Ajax /ˈeɪdʒæks/ is a carbonaceous Jupiter trojan from the Greek camp, approximately 83 kilometers (52 miles) kilometers in diameter. It was discovered on 17 August 1936, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany, and named after the legendary warrior Ajax from Greek mythology.^[1] The assumed C-type asteroid belongs to the 40 largest Jupiter trojans and has a longer than average rotation period of 29.4 hours.^[5]

Orbit and classification

Ajax is a C-type asteroid, that orbits in the leading Greek camp at Jupiter's L₄ Lagrangian point, 60° ahead of its orbit (see Trojans in astronomy). It is also a non-family asteroid in the Jovian background population.^[7][15] Jupiter trojans are thought to have been captured into their orbits during or shortly after the early stages of the formation of the Solar System. More than 4,500 Jupiter trojans in the Greek camp and 7,000 in total have been discovered.^[6]

It orbits the Sun at a distance of 4.7–5.9 AU once every 12 years and 3 months (4,459 days; semi-major axis of 5.3 AU). Its orbit has an eccentricity of 0.11 and an inclination of 18° with respect to the ecliptic.^[4] The body's observation arc begins at Heidelberg 6 days after its official discovery observations in August 1936.^[1]

Physical characteristics

Ajax is an assumed, carbonaceous C-type asteroid, while its V–I color index of 0.96 agrees with most D-type asteroids, which is the dominant spectral type among the large Jupiter trojans.^[5]

Naming

This minor planet was named for Ajax the Great, a Greek warrior of great strength and courage in the Trojan War. He is the half brother of Teucer and son of king Telamon, who kills himself because Achilles' armor was awarded to Odysseus. The Jupiter trojans 588 Achilles, 1143 Odysseus and 1749 Telamon and 2797 Teucer are all named after these figures from Greek mythology.^[3] The official naming of Ajax was first cited in The Names of the Minor Planets by Paul Herget in 1955 (H 127).^[3]

References

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 1404 Ajax at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 1404 Ajax at the JPL Small-Body Database