| Discovery[1] | |
|---|---|
| Discovered by | C. Kowal |
| Discovery site | Palomar Obs. |
| Discovery date | 4 October 1978 |
| Designations | |
| (2594) Acamas | |
| Pronunciation | /ˈækəməs/[2] |
Named after | Acamas(Greek mythology)[1] |
| 1978 TB · 1977 RR | |
| Jupiter trojan[1][3] Trojan[4] · background[5] | |
| Orbital characteristics[3] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 64.44yr (23,537 d) |
| Aphelion | 5.4911AU |
| Perihelion | 4.6313 AU |
| 5.0612 AU | |
| Eccentricity | 0.0849 |
| 11.39 yr (4,159 d) | |
| 242.01° | |
| 0° 5m 11.76s / day | |
| Inclination | 5.5341° |
| 356.69° | |
| 279.28° | |
| Jupiter MOID | 0.082 AU |
| TJupiter | 2.9840 |
| Physical characteristics | |
| 25.87±0.59 km[6] | |
| 25.954±0.0468 h(R)[7][8] | |
| 0.060±0.006[6] | |
| C(assumed)[7] | |
| 11.6[6] 11.8[1][3] 12.31[7] | |
2594 Acamas/ˈækəməs/ is a mid-sizedJupiter trojan from theTrojan camp, approximately 25 kilometers (16 miles) in diameter. It was discovered on 4 October 1978, by American astronomerCharles Kowal at thePalomar Observatory in California.[1] The dark Jovianasteroid has a longer-than averagerotation period of 26 hours and possibly an elongated shape.[7] It was named after the Thracian leaderAcamas from Greek mythology.[1]
Acamas is a dark Jovianasteroid in a 1:1orbital resonance with Jupiter. It is located in the traileringTrojan camp at the Gas Giant'sL5Lagrangian point, 60° behind on its orbit(seeTrojans in astronomy). It is also a non-family asteroid of theJovian background population.[5]
It orbits the Sun at a distance of 4.6–5.5 AU once every 11 years and 5 months (4,159 days;semi-major axis of 5.06 AU). Its orbit has aneccentricity of 0.08 and aninclination of 6° with respect to theecliptic.[3] The body'sobservation arc begins with aprecovery taken at Palomar in September 1953, or 25 years prior to its official discovery observation.[1]
Acamas is an assumed, carbonaceousC-type asteroid, while most larger Jupiter trojans areD-type asteroids.[7]
In September 2013, a rotationallightcurve ofAcamas was obtained fromphotometric observations in the R-band by astronomers at thePalomar Transient Factory in California. Lightcurve analysis gave arotation period of25.954±0.0468 hours with a brightness amplitude of 0.50magnitude (U=2).[7][8] A high brightness variation typically indicates that the body has an elongated rather than spherical shape.
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Acamas measures 25.87 kilometers in diameter and its surface has analbedo 0.06,[6] while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 19.21 kilometers based on anabsolute magnitude of 12.31.[7]
Thisminor planet was named byIAU'sMinor Planet Names Committee fromGreek mythology after the warriorAcamas (son of Eussorus), ally of Troy and leader of the Thracian contingent during theTrojan War. He was killed byAjax.[1]
The name was suggested byFrederick Pilcher and published by theMinor Planet Center on 6 February 1993 (M.P.C. 21606).[1][9]
