Astronomy:4057 Demophon

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4057 Demophon
Discovery [1]
Discovered byE. Bowell
Discovery siteAnderson Mesa Stn.
Discovery date15 October 1985
Designations
(4057) Demophon
Pronunciation/ˈdɛməfɒn/[5]
Named afterDemophon of Athens [1]
(Greek mythology)
1985 TQ
Minor planet categoryJupiter trojan [1][2]
Greek [3] · background [4]
AdjectivesDemophontian
Orbital characteristics [2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc32.65 yr (11,927 d)
|{{{apsis}}}|helion}}5.8832 AU
|{{{apsis}}}|helion}}4.6425 AU
5.2628 AU
Eccentricity0.1179
Orbital period12.07 yr (4,410 d)
Mean anomaly197.56°
Mean motion0° 4m 53.76s / day
Inclination2.8706°
Longitude of ascending node24.383°
58.875°
Jupiter MOID0.0724 AU
TJupiter2.9840
Physical characteristics
Mean diameter45.68±6.58 km[6]
53.16 km (calculated)[7]
Rotation period29.82±0.24 h[8]
Geometric albedo0.057 (assumed)[7]
0.077±0.015[6]
C (assumed)[7]
V–I = 1.060±0.037[7]
Absolute magnitude (H)10.1[1][2][6][7]


4057 Demophon /ˈdɛməfɒn/ is a larger Jupiter trojan from the Greek camp, approximately 46 kilometers (29 miles) in diameter. It was discovered on 15 October 1985 by American astronomer Edward Bowell at the Anderson Mesa Station of the Lowell Observatory near Flagstaff, Arizona.[1] The dark Jovian asteroid has a longer-than-average rotation period of 29.8 hours.[7] It was named after the Athen prince Demophon who fought in the Trojan War.[1]

Orbit and classification

Demophon is a dark Jovian asteroid 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). It is also a non-family asteroid of the Jovian background population.[4]

It orbits the Sun at a distance of 4.6–5.9 AU once every 12 years and 1 month (4,410 days; semi-major axis of 5.26 AU). Its orbit has an eccentricity of 0.12 and an inclination of 3° with respect to the ecliptic.[2] The body's observation arc begins with a precovery taken at Crimea–Nauchnij in September 1985, just three weeks prior to its official discovery observation at Anderson Mesa.[1]

Physical characteristics

Demophon is an assumed, carbonaceous C-type asteroid. It has a high V–I color index of 1.06.[7] Most larger Jupiter trojans are D-type asteroids.

Rotation period

In June 1994, a first rotational lightcurve of Demophon was obtained from photometric observations by Stefano Mottola and Anders Erikson using the Dutch 0.9-metre Telescope at ESO's La Silla Observatory in Chile. Lightcurve analysis gave a rotation period of 29.31 hours with a brightness variation of 0.23 magnitude ({{{1}}}).[9]

In August 2015, photometric observations by the Kepler space telescope rendered another two lightcurves ({{{1}}}).[7][8][10] The best-rated one showed a period of 29.82±0.24 hours and a brightness variation of 0.21 magnitude.[8] Most asteroids have a shorter rotation period between 2 and 20 hours (also see List of slow rotators).

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Demophon measures 45.68 kilometers in diameter and its surface has an albedo of 0.077,[6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 53.16 kilometers based on an absolute magnitude of 10.1.[7]

100+ largest Jupiter trojans

Naming

This minor planet was named from Greek mythology after the Athen prince Demophon, son of King Theseus and Phaedra. After participation in the Trojan War, Demophon married Phyllis, who committed suicide after he had abandoned her.[1] The official naming citation was published by the Minor Planet Center on 22 April 1997 (M.P.C. 29669).[11]

References

  1. ↑ Jump up to: 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 "4057 Demophon (1985 TQ)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=4057. 
  2. ↑ Jump up to: 2.0 2.1 2.2 2.3 "JPL Small-Body Database Browser: 4057 Demophon (1985 TQ)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004057. 
  3. ↑ "List of Jupiter Trojans". Minor Planet Center. 1 June 2018. https://www.minorplanetcenter.net/iau/lists/JupiterTrojans.html. 
  4. ↑ Jump up to: 4.0 4.1 "Asteroid (4057) Demophon – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. https://newton.spacedys.com/astdys/index.php?n=4057&pc=1.1.6. 
  5. ↑ Noah Webster (1884) A Practical Dictionary of the English Language
  6. ↑ Jump up to: 6.0 6.1 6.2 6.3 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. Bibcode: 2012ApJ...759...49G.  (online catalog)
  7. ↑ Jump up to: 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 "LCDB Data for (4057) Demophon". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=4057%7CDemophon. 
  8. ↑ Jump up to: 8.0 8.1 8.2 Ryan, Erin Lee; Sharkey, Benjamin N. L.; Woodward, Charles E. (March 2017). "Trojan Asteroids in the Kepler Campaign 6 Field". The Astronomical Journal 153 (3): 12. doi:10.3847/1538-3881/153/3/116. Bibcode: 2017AJ....153..116R. 
  9. ↑ Mottola, Stefano; Di Martino, Mario; Erikson, Anders; Gonano-Beurer, Maria; Carbognani, Albino; Carsenty, Uri et al. (May 2011). "Rotational Properties of Jupiter Trojans. I. Light Curves of 80 Objects". The Astronomical Journal 141 (5): 32. doi:10.1088/0004-6256/141/5/170. Bibcode: 2011AJ....141..170M. 
  10. ↑ Szabó, Gy. M.; Pál, A.; Kiss, Cs.; Kiss, L. L.; Molnár, L.; Hanyecz, O. et al. (March 2017). "The heart of the swarm: K2 photometry and rotational characteristics of 56 Jovian Trojan asteroids". Astronomy and Astrophysics 599: 13. doi:10.1051/0004-6361/201629401. Bibcode: 2017A&A...599A..44S. 
  11. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html. 

External links



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