|Discovered by||C. J. van Houten|
I. van Houten-G.
|Discovery site||Palomar Obs.|
|Discovery date||24 September 1960|
|MPC designation||(11429) Demodokus|
|4655 P-L · 1996 RZ32|
|Jupiter trojan |
Greek  · background 
|Orbital characteristics |
|Epoch 23 March 2018 (JD 2458200.5)|
|Uncertainty parameter 0|
|Observation arc||57.65 yr (21,056 d)|
|12.04 yr (4,397 d)|
|0° 4m 54.84s / day|
|Jupiter MOID||0.2122 AU|
46.30 km (calculated)
11429 Demodokus (// dee-MOD-ə-kəs), provisional designation 4655 P-L, is a mid-sized Jupiter trojan from the Greek camp, approximately 38 kilometers (24 miles) in diameter. It was discovered during the Palomar–Leiden survey at the Palomar Observatory in 1960 and later named after the blind singer Demodocus from Greek mythology. The dark Jovian asteroid has a longer-than average rotation period of 50.2 hours.
Demodokus was discovered on 24 September 1960, by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by astronomer Tom Gehrels at the Palomar Observatory in California. The body's observation arc begins with its official discovery observation at Palomar.
The survey designation "P-L" stands for "Palomar–Leiden", named after Palomar Observatory and Leiden Observatory, which collaborated on the fruitful Palomar–Leiden survey in the 1960s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of several thousand asteroids.
This minor planet was named from Greek mythology after Demodocus, the blind singer at the court of King Alcinous, who is the ruler of the Phaiacians in Homer's Odyssey. The official naming citation was published by the Minor Planet Center on 24 January 2000 (M.P.C. 38201).
Orbit and classification
Demodokus is a dark Jupiter trojan in a 1:1 orbital resonance with Jupiter. It is located in the leading Greek camp at the Gas Giant's L4 Lagrangian point, 60° ahead on its orbit . It is also a non-family asteroid of the Jovian background population. It orbits the Sun at a distance of 5.1–5.4 AU once every 12.04 years (4,397 days; semi-major axis of 5.25 AU). Its orbit has an eccentricity of 0.03 and an inclination of 17° with respect to the ecliptic.
In February 2014, a rotational lightcurve of Demodokus was obtained over five consecutive nights of photometric observations by Robert Stephens at the Center for Solar System Studies. Lightcurve analysis gave a longer-than average rotation period of 50.16±0.06 hours with a relatively low brightness amplitude of 0.18 magnitude (U=2).[a]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Demodokus measures 37.63 kilometers in diameter and its surface has an albedo of 0.086, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 46.3 kilometers based on an absolute magnitude of 10.4.
- "11429 Demodokus (4655 P-L)". Minor Planet Center. Retrieved 3 July 2018.
- "JPL Small-Body Database Browser: 11429 Demodokus (4655 P-L)" (2018-05-19 last obs.). Jet Propulsion Laboratory. Retrieved 3 July 2018.
- "List of Jupiter Trojans". Minor Planet Center. 1 July 2018. Retrieved 3 July 2018.
- "Asteroid (11429) Demodokus – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 3 July 2018.
- 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. arXiv:1209.1549. Bibcode:2012ApJ...759...49G. doi:10.1088/0004-637X/759/1/49. Retrieved 3 July 2018. (online catalog)
- "LCDB Data for (11429) Demodokus". Asteroid Lightcurve Database (LCDB). Retrieved 3 July 2018.
- Stephens, Robert D.; Coley, Daniel R.; French, Linda M. (October 2014). "Trojan Asteroids Observed from CS3: 2014 January-May". The Minor Planet Bulletin. 41 (4): 210–212. Bibcode:2014MPBu...41..210S. ISSN 1052-8091. Retrieved 3 July 2018.
- "Minor Planet Discoverers". Minor Planet Center. 2018. Retrieved 3 July 2018.
- "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 3 July 2018.
- Asteroid Lightcurve Database (LCDB), query form (info)
- Dictionary of Minor Planet Names, Google books
- Discovery Circumstances: Numbered Minor Planets (10001)-(15000) – Minor Planet Center
- Asteroid 11429 Demodokus at the Small Bodies Data Ferret
- 11429 Demodokus at AstDyS-2, Asteroids—Dynamic Site
- 11429 Demodokus at the JPL Small-Body Database