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5284 Orsilocus

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5284 Orsilocus
Discovery [1]
Discovered byC. S. Shoemaker
E. M. Shoemaker
Discovery sitePalomar Obs.
Discovery date1 February 1989
Designations
(5284) Orsilocus
Pronunciation/ɔːrˈsɪləkəs/[2]
Named after
Orsilochus (Orsilocus) [1]
(Greek mythology)
1989 CK2
Jupiter trojan [1][3]
Greek [4] · background [5]
AdjectivesOrsilocian
Orbital characteristics [3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc65.27 yr (23,840 d)
Aphelion5.6580 AU
Perihelion4.7937 AU
5.2259 AU
Eccentricity0.0827
11.95 yr (4,364 d)
203.67°
0° 4m 57s / day
Inclination20.225°
102.75°
343.29°
Jupiter MOID0.3804 AU
TJupiter2.8700
Physical characteristics
50.16±0.46 km[6]
53.16 km (calculated)[7]
10.31±0.01 h[8][a]
0.057 (assumed)[7]
0.070±0.009[6]
D (Pan-STARRS)[7][9]
D (SDSS-MOC)[10]
V–I = 0.970±0.047[7]
10.0[6]
10.1[1][3][7]
10.28±0.24[9]

5284 Orsilocus /ɔːrˈsɪləkəs/ is a Jupiter trojan from the Greek camp, approximately 50 kilometers (31 miles) in diameter. It was discovered on 1 February 1989, by American astronomers Carolyn and Eugene Shoemaker at the Palomar Observatory in California.[1] The D-type asteroid belongs the 100 largest Jupiter trojans and has a rotation period of 10.3 hours.[7] It was named after the hero Orsilochus (Orsilocus) from Greek mythology.[1]

Orbit and classification[edit]

Orsilocus is a dark Jovian asteroid orbiting in the leading Greek camp at Jupiter's L4 Lagrangian point, 60° ahead of the Gas Giant's orbit in a 1:1 resonance (see Trojans in astronomy).[4] It is also a non-family asteroid in the Jovian background population.[5]

It orbits the Sun at a distance of 4.8–5.7 AU once every 11 years and 11 months (4,364 days; semi-major axis of 5.23 AU). Its orbit has an eccentricity of 0.08 and an inclination of 20° with respect to the ecliptic.[3] The body's observation arc begins with a precovery at Palomar in February 1953, or 36 years prior to its official discovery observation.[1]

Physical characteristics[edit]

In the SDSS-based taxonomy, Orsilocus is a D-type asteroid,[10][11] the most common spectral type among the larger Jupiter trojans. It has also been characterized as a D-type by Pan-STARRS' survey, while the Collaborative Asteroid Lightcurve Link (CALL) assumes it to be a carbonaceous C-type asteroid.[7][9] Its V–I color index of 0.97 is typical for most larger Jovian asteroids.[7]

Rotation period[edit]

In February 2013, a rotational lightcurve of Orsilocus was obtained from photometric observations by Robert Stephens at the Center for Solar System Studies (CS3) in Landers, California. Lightcurve analysis gave a rotation period of 10.31±0.01 hours with a variation amplitude of 0.12 magnitude (U=2+).[7][8][a]

In 2015 and 2016, follow-up observations by Stephens at the CS3 gave two concurring periods of 10.28±0.01 and 10.36±0.03 hours with an amplitude of 0.20 and 0.16 magnitude, respectively (U=2+/2+).[7][12][13][a]

Diameter and albedo[edit]

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Orsilocus measures 50.16 kilometers in diameter and its surface has an albedo of 0.070,[6] while CALL 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[edit]

This minor planet was named from Greek mythology after Orsilochus, son of Diocles (Diokles) and twin brother of Crethon (see 5285 Krethon). The Achaean warrior fought under Agamemnon and Menelaus in the Trojan War, where he was slain by Aeneas.[1] The official naming citation was published by the Minor Planet Center on 12 July 1995 (M.P.C. 25444).[14]

Notes[edit]

  1. ^ Jump up to: a b c Lightcurve plot of (5284) Orsilocus from Feb 2013, May 2015 and May 2016 by Robert Stephens at the Center for Solar System Studies (U81). Quality code is n.a./2+/2+ (lightcurve rating at CS3). Summary figures at the LCDB and CS3.

References[edit]

  1. ^ Jump up to: a b c d e f g h "5284 Orsilocus (1989 CK2)". Minor Planet Center. Retrieved 20 June 2018.
  2. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  3. ^ Jump up to: a b c d "JPL Small-Body Database Browser: 5284 Orsilocus (1989 CK2)" (2018-05-25 last obs.). Jet Propulsion Laboratory. Retrieved 20 June 2018.
  4. ^ Jump up to: a b "List of Jupiter Trojans". Minor Planet Center. 1 June 2018. Retrieved 20 June 2018.
  5. ^ Jump up to: a b "Asteroid (5284) Orsilocus – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 20 June 2018.
  6. ^ Jump up to: 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. ^ Jump up to: a b c d e f g h i j k "LCDB Data for (5284) Orsilocus". Asteroid Lightcurve Database (LCDB). Retrieved 20 June 2018.
  8. ^ Jump up to: a b French, Linda M.; Stephens, Robert, D.; Coley, Daniel R.; Wasserman, Lawrence H.; Vilas, Faith; La Rocca, Daniel (October 2013). "A Troop of Trojans: Photometry of 24 Jovian Trojan Asteroids". The Minor Planet Bulletin. 40 (4): 198–203. Bibcode:2013MPBu...40..198F. ISSN 1052-8091.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ Jump up to: 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. ^ Jump up to: 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. ^ "Asteroid 5284 Orsilocus". Small Bodies Data Ferret. Retrieved 20 June 2018.
  12. ^ Stephens, Robert D.; Coley, Daniel, R.; French, Linda M. (January 2016). "Large L5 Jovian Trojan Asteroid Lightcurves from the Center for Solar System Studies". The Minor Planet Bulletin. 43 (1): 15–22. Bibcode:2016MPBu...43...15S. ISSN 1052-8091.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ^ 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)
  14. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 20 June 2018.

External links[edit]

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