4708 Polydoros


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4708 Polydoros is a Jupiter trojan from the Trojan camp, approximately 55 kilometers (34 miles) in diameter. It was discovered on 11 September 1988, by American astronomer Carolyn Shoemaker at the Palomar Observatory in California.[1] The D-type asteroid belongs to the 80 largest Jupiter trojans and has a rotation period of 7.5 hours.[7] It was named after the Trojan prince Polydorus, from Greek mythology.[1]

4708 Polydoros
Discovery [1]
Discovered byC. Shoemaker
Discovery sitePalomar Obs.
Discovery date11 September 1988
Designations
(4708) Polydoros
Pronunciation[2]

Named after

Polydorus
(Greek mythology)[1]
1988 RT
Jupiter trojan [1][3]
Trojan [4] · background [5]
AdjectivesPolydorian
Orbital characteristics [3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc29.70 yr (10,847 d)
Aphelion5.5674 AU
Perihelion4.9467 AU
5.2570 AU
Eccentricity0.0590
12.05 yr (4,403 d)
123.79°
0° 4m 54.48s / day
Inclination6.9857°
281.17°
103.97°
Jupiter MOID0.019 AU
TJupiter2.9820
Physical characteristics
54.96±0.55 km[6]
55.67 km (calculated)[7]
7.517±0.001 h[8][a]
0.057 (assumed)[7]
0.064±0.005[6]
D (Pan-STARRS)[7][9]
D (SDSS-MOC)[10]
B–V = 0.770±0.060[11]
V–R = 0.520±0.040[11]
V–I = 0.960±0.040[7]
9.9[1][3][6]
10.0[7]
10.18±0.10[9]

Orbit and classification

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Polydoros is a Jovian asteroid located in the L5 Lagrangian point, 60° behind on Jupiter's orbit in the so-called Trojan camp (see Trojans in astronomy).[4] It is also a non-family asteroid of the Jovian background population.[5]

It orbits the Sun at a distance of 4.9–5.6 AU once every 12 years and 1 month (4,403 days; semi-major axis of 5.26 AU). Its orbit has an eccentricity of 0.06 and an inclination of 7° with respect to the ecliptic.[3] The body's observation arc begins with its official discovery observation at Palomar in September 1988.[1]

Physical characteristics

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In the SDSS-based taxonomy, Polydoros is a dark D-type asteroid.[10] It has also been characterized as a D-type by Pan-STARRS' survey.[7][9] Its V–I color index of 0.96 is typical for most larger D-type Jupiter trojans (see table below).[7]

In August 2011, a rotational lightcurve of Polydoros was obtained from photometric observations by Linda French at the Cerro Tololo Inter-American Observatory in Chile. Lightcurve analysis, however, gave an incorrect rotation period of 20.03 hours with a brightness variation of 0.25 magnitude (U=0).[7][12]

Several subsequent observations during 2014–2018 by Daniel Coley and Robert D. Stephens at the Center for Solar System Studies achieved a good period determination,[8][13][a] with the best-rated one from November 2015, which gave a period of 7.517±0.001 hours and an amplitude of 0.17 magnitude (U=3).[7][8]

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Polydoros measures 54.96 kilometers in diameter and its surface has an albedo of 0.064,[6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057, and calculates a diameter of 55.67 kilometers based on an absolute magnitude of 10.0.[7]

This minor planet was named by the discoverer from Greek mythology after the Trojan prince Polydorus, the youngest and swiftest of King Priam's many sons. Although forbidden by his father, Polydoros confronted Achilles anyway, and was killed by him beside the River Scamander, near his brother Lycaon (also see 4792 Lykaon).[1] The official naming citation was published by the Minor Planet Center on 28 April 1991 (M.P.C. 18144).[14]

  1. ^ a b Lightcurve plots of (4708) Polydoros from 2014, 2015, 2017, and 2018, by Daniel Coley and Robert Stephens at the Center for Solar System Studies (U81). Quality code is: 3-/3/3-/3- (lightcurve rating at CS3). Summary figures at the LCDB and CS3.
  1. ^ a b c d e f g h "4708 Polydoros (1988 RT)". Minor Planet Center. Retrieved 18 June 2018.
  2. ^ 'Polydorus' in Noah Webster (1884) A Practical Dictionary of the English Language
  3. ^ a b c d "JPL Small-Body Database Browser: 4708 Polydoros (1988 RT)" (2018-05-24 last obs.). Jet Propulsion Laboratory. Retrieved 18 June 2018.
  4. ^ a b "List of Jupiter Trojans". Minor Planet Center. 1 June 2018. Retrieved 18 June 2018.
  5. ^ a b "Asteroid (4708) Polydoros – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 18 June 2018.
  6. ^ a b c d 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. S2CID 119101711. (online catalog)
  7. ^ a b c d e f g h i j k "LCDB Data for (4708) Polydoros". Asteroid Lightcurve Database (LCDB). Retrieved 18 June 2018.
  8. ^ a b c Stephens, Robert D.; Coley, Daniel R.; Warner, Brian D.; French, Linda, M. (October 2016). "Lightcurves of Jovian Trojan Asteroids from the Center for Solar System Studies: L4 Greek Camp and Spies". The Minor Planet Bulletin. 43 (4): 323–331. Bibcode:2016MPBu...43..323S. ISSN 1052-8091.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ a b c Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. S2CID 53493339.
  10. ^ a b Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics. 510: 12. Bibcode:2010A&A...510A..43C. doi:10.1051/0004-6361/200913322. Retrieved 30 October 2019. (PDS data set)
  11. ^ a b Chatelain, Joseph P.; Henry, Todd J.; French, Linda M.; Winters, Jennifer G.; Trilling, David E. (June 2016). "Photometric colors of the brightest members of the Jupiter L5 Trojan cloud". Icarus. 271: 158–169. Bibcode:2016Icar..271..158C. doi:10.1016/j.icarus.2016.01.026.
  12. ^ French, Linda M.; Stephens, Robert D.; Coley, Daniel R.; Megna, Ralph; Wasserman, Lawrence H. (July 2012). "Photometry of 17 Jovian Trojan Asteroids". The Minor Planet Bulletin. 39 (3): 183–187. Bibcode:2012MPBu...39..183F. ISSN 1052-8091.
  13. ^ Stephens, Robert D.; Coley, Daniel R.; French, Linda M. (July 2015). "Dispatches from the Trojan Camp - Jovian Trojan L5 Asteroids Observed from CS3: 2014 October - 2015 January". The Minor Planet Bulletin. 42 (3): 216–224. Bibcode:2015MPBu...42R.216S. ISSN 1052-8091.
  14. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 18 June 2018.