Astronomy:11429 Demodokus

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11429 Demodokus
011429-asteroid shape model (11429) Demodokus.png
Shape model of Demodokus from its lightcurve
Discovery[1]
Discovered byC. J. van Houten
I. van Houten-G.
T. Gehrels
Discovery sitePalomar Obs.
Discovery date24 September 1960
Designations
(11429) Demodokus
Pronunciation/dɪˈmɒdəkəs/
Named afterΔημόδοκος Dēmodokos[1]
(Greek mythology)
4655 P-L · 1996 RZ32
PLS4655
Minor planet categoryJupiter trojan[1][2]
Greek[3] · background[4]
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc57.65 yr (21,056 d)
|{{{apsis}}}|helion}}5.3994 AU
|{{{apsis}}}|helion}}5.1057 AU
5.2525 AU
Eccentricity0.0280
Orbital period12.04 yr (4,397 d)
Mean anomaly173.02°
Mean motion0° 4m 54.84s / day
Inclination17.081°
Longitude of ascending node6.3025°
89.223°
Jupiter MOID0.2122 AU
TJupiter2.9110
Physical characteristics
Mean diameter37.63±1.31 km[5]
46.30 km (calculated)[6]
Rotation period50.16±0.06 h[7][lower-alpha 1]
Geometric albedo0.057 (assumed)[6]
0.086±0.017[5]
C (assumed)[6]
Absolute magnitude (H)10.40[1][2][5][6]


11429 Demodokus /dɪˈmɒdəkəs/ 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.[1] The dark Jovian asteroid has a longer-than average rotation period of 50.2 hours.[6]

Discovery

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.[1] The body's observation arc begins with its official discovery observation at Palomar.[1]

Palomar–Leiden survey

Naming

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.[1] The official naming citation was published by the Minor Planet Center on 24 January 2000 (M.P.C. 38201).[8]

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 (see Trojans in astronomy).[3] It is also a non-family asteroid of the Jovian background population.[4] 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.[2]

Physical characteristics

Demodokus is an assumed C-type asteroid, while the majority of larger Jupiter trojans are D-types.[6]

Rotation period

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 ({{{1}}}).[1][lower-alpha 1]

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,[5] 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.[6]

100+ largest Jupiter trojans

Notes

  1. Jump up to: 1.0 1.1 Lightcurve plots of (11429) Demodokus from Feb 2014 by Robert Stephens at the Center for Solar System Studies (U81). Quality code is 2+ (lightcurve rating at CS3). Summary figures at the LCDB and CS3.

References

  1. Jump up to: 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 "11429 Demodokus (4655 P-L)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=11429. Retrieved 3 July 2018. 
  2. Jump up to: 2.0 2.1 2.2 2.3 "JPL Small-Body Database Browser: 11429 Demodokus (4655 P-L)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2011429. Retrieved 3 July 2018. 
  3. Jump up to: 3.0 3.1 "List of Jupiter Trojans". Minor Planet Center. 1 July 2018. https://www.minorplanetcenter.net/iau/lists/JupiterTrojans.html. Retrieved 3 July 2018. 
  4. Jump up to: 4.0 4.1 "Asteroid (11429) Demodokus – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. https://newton.spacedys.com/astdys/index.php?n=11429&pc=1.1.6. 
  5. Jump up to: 5.0 5.1 5.2 5.3 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. doi:10.1088/0004-637X/759/1/49. Bibcode2012ApJ...759...49G. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012ApJ...759...49G. Retrieved 3 July 2018.  (online catalog)
  6. Jump up to: 6.0 6.1 6.2 6.3 6.4 6.5 6.6 "LCDB Data for (11429) Demodokus". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=11429%7CDemodokus. Retrieved 3 July 2018. 
  7. 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. ISSN 1052-8091. Bibcode2014MPBu...41..210S. http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014MPBu...41..210S. Retrieved 3 July 2018. 
  8. "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html. Retrieved 3 July 2018. 
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External links