5511 Cloanthus

Hubble Space Telescope image ofCloanthus taken in 2012
Discovery [1]
Discovered by	C. S. Shoemaker E. M. Shoemaker
Discovery site	Palomar Obs.
Discovery date	8 October 1988
Designations
MPC designation	(5511) Cloanthus
Pronunciation	/kloʊˈænθəs/
Named after	Cloanthus [1] (Greco-Roman mythology)
Alternative designations	1988 TH1 · 1989 VU3 1989 WA7
Minor planet category	Jupiter trojan [1][2] Trojan [3] · background [4]
Orbital characteristics [2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	66.82yr (24,405 d)
Aphelion	5.8529AU
Perihelion	4.6339 AU
Semi-major axis	5.2434 AU
Eccentricity	0.1162
Orbital period (sidereal)	12.01 yr (4,385 d)
Mean anomaly	240.47°
Mean motion	0° 4m 55.56s / day
Inclination	11.167°
Longitude of ascending node	172.67°
Argument of perihelion	121.33°
Jupiter MOID	0.0098 AU
TJupiter	2.9490
Physical characteristics
Mean diameter	39.77±0.43 km[5] 48.48 km(assumed)[6]
Synodic rotation period	336±7 h[7]
Geometric albedo	0.057(assumed)[6] 0.093±0.013[5]
Spectral type	C (assumed)[6] B–V =0.690±0.060[8] V–R =0.480±0.040[8] V–I =0.890±0.044[6] BR =1.210±0.057[6]
Absolute magnitude (H)	10.20[5] 10.3[1][2][6]

5511 Cloanthus/kloʊˈænθəs/ is aJupiter trojan from theTrojan camp, approximately 40 kilometers (25 miles) in diameter. It was discovered on 8 October 1988, by American astronomer coupleCarolyn andEugene Shoemaker at thePalomar Observatory in California.^[1] The dark and likely elongated Jovianasteroid is aslow rotator with a longrotation period of possibly 336 hours.^[6] It was named after the wandering TrojanCloanthus from Classical mythology.^[1]

Cloanthus is a dark Jovianasteroid in a 1:1orbital resonance withJupiter. It is located in the trailingTrojan camp at itsL₅Lagrangian point, 60° behind its orbit(seeTrojans in astronomy).^[3] It is also a non-family asteroid of theJovian background population.^[4] It orbits the Sun at a distance of 4.6–5.9 AU once every 12 years (4,385 days;semi-major axis of 5.24 AU). Its orbit has aneccentricity of 0.12 and aninclination of 11° with respect to theecliptic.^[2] The body'sobservation arc begins with aprecovery taken at Palomar in July 1951, more than 37 years prior to its official discovery observation.^[1]

Thisminor planet was named from Greco-Roman mythology after the TrojanCloanthus, a companion ofAeneas in Classical mythology. He is one of the wanderingAeneads who traveled to Italy after the downfall of Troy. At the funeral games for Aeneas' father,Anchises, Cloanthus was the winner of the boat race because he called upon the gods of the sea to help him with his heavier ship.^[1] The official naming citation was published by theMinor Planet Center on 12 July 1995 (M.P.C. 25444).^[9] Other Jovian asteroids named after members of the Aeneads include4827 Dares,4828 Misenus,5120 Bitias and9023 Mnesthus.

Cloanthus is an assumed, carbonaceousC-type asteroid.^[6] Most Jupiter trojans areD-types, with the remainder being mostly C andP-type asteroids. It has aV–I color index of 0.890 and aBR color of 1.21(also see table below).^[6]

In July 2010, a rotationallightcurve ofCloanthus was obtained fromphotometric observations by Italian astronomerStefano Mottola using the 1.2-meter telescope atCalar Alto Observatory in Spain. Lightcurve analysis gave a very longrotation period of336±7 hours with a high brightness amplitude of at least 0.49magnitude, indicative of an elongated, rather than spherical shape.^[6][7] Due to the lightcurve's low quality rating (U=2-), it is only apotentially slow rotator.^[6]

According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Cloanthus measures 39.77 kilometers in diameter and its surface has analbedo of 0.093,^[5] while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 48.48 kilometers based on anabsolute magnitude of 10.3.^[6]

• 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 (5001)-(10000) – Minor Planet Center
• Asteroid 5511 Cloanthus at the Small Bodies Data Ferret
• 5511 Cloanthus atAstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 5511 Cloanthus 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 Carolyn S. Shoemaker
• Discoveries by Eugene Merle Shoemaker
• Named minor planets
• Slow rotating minor planets
• Astronomical objects discovered in 1988

• Use dmy dates from June 2018
• Webarchive template wayback links