15440 Eioneus

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15440 Eioneus
Discovery [1][2]
Discovered byCSS
Discovery siteCatalina Stn.
Discovery date19 November 1998
Designations
(15440) Eioneus
Named after
Eioneus [3]
(Greek mythology)
1998 WX4 · 1992 LD
Minor planet category
Jupiter trojan [1][4][5]
Greek [6][7] · background [7]
Orbital characteristics [4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc66.48 yr (24,280 d)
Aphelion5.4151 AU
Perihelion5.1821 AU
5.2986 AU
Eccentricity0.0220
12.20 yr (4,455 d)
240.92°
0° 4m 50.88s / day
Inclination28.743°
120.55°
279.64°
Jupiter MOID0.0063 AU
TJupiter2.7510
Physical characteristics
Mean diameter
62.52±0.83 km[8]
66.48±3.8 km[9]
71.88±3.87 km[10]
21.43±0.02 h[5][11][a]
0.072±0.011[8]
0.079±0.009[10]
0.0916±0.011[9]
C (assumed)[5]
V–I = 0.970±0.041[5]
Absolute magnitude (H)
9.10[10]
9.5[8]
9.6[1][4][5]
9.68±0.31[12]

15440 Eioneus, provisional designation: 1998 WX4, is a dark Jupiter trojan from the Greek camp, approximately 66 kilometers (41 miles) in diameter. It was discovered on 19 November 1998, by astronomers with the Catalina Sky Survey at the Catalina Station near Tucson, Arizona, in the United States.[1] The assumed C-type asteroid belongs to the 60 largest Jupiter trojans. It has a rotation period of 21.43 hours and possibly a spherical shape.[5] It was named from Greek mythology after Eioneus who was killed by Hector.[3]

Orbit and classification[]

Eioneus 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). It is also a non-family asteroid in the Jovian background population.[7]

It orbits the Sun at a distance of 5.2–5.4 AU once every 12 years and 2 months (4,455 days; semi-major axis of 5.3 AU). Its orbit has an eccentricity of 0.02 and an inclination of 29° with respect to the ecliptic.[4] The body's observation arc begins with a precovery published by the Digitized Sky Survey and taken at the Palomar Observatory in November 1951, or 47 years prior to its official discovery observation at Catalina.[1]

Naming[]

This minor planet was numbered on 21 June 2000 (M.P.C. 40826).[13] On 14 May 2021, the object was named from Greek mythology by the Working Group Small Body Nomenclature (WGSBN), after the Greek warrior Eioneus who was killed by a spear from Hector during the Trojan War.[3]

Physical characteristics[]

Eioneus is an assumed C-type asteroid, while the majority of large Jupiter trojans are D-types. It has a typical V–I color index of 0.97.[5]

Rotation period[]

Since January 2013, a large number of a rotational lightcurve of Eioneus have been obtained from photometric observations by Robert Stephens at the Center for Solar System Studies in California.[14][15][11][a] Analysis of the best-rated lightcurve from June 2017 gave a longer-than-average rotation period of 21.43±0.02 h hours with a low brightness amplitude of 0.09±0.02 magnitude (U=2+), indicative of a rather spherical shape.[5][11]

Diameter and albedo[]

According to the surveys carried out by the Japanese Akari satellite, the Infrared Astronomical Satellite IRAS and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Eioneus measures between 62.52 and 71.88 kilometers in diameter and its surface has an albedo between 0.072 and 0.092.[8][9][10] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0585 and a diameter of 66.04 kilometers based on an absolute magnitude of 9.6.[5]

100+ largest Jupiter trojans

Notes[]

  1. ^ Jump up to: a b Lightcurve plots of (15440) 1998 WX4 from 2013, 2014, 2015, 2016 and 2017 by Robert Stephens at the Center for Solar System Studies (U81). Quality code is n.a/n.a/2+/3-/3-. (lightcurve rating at CS3). Summary figures at the LCDB and CS3.

References[]

  1. ^ Jump up to: a b c d e "15440 (1998 WX4)". Minor Planet Center. Retrieved 14 June 2018.
  2. ^ "Asteroid (15440) 1998 WX4". Small Bodies Data Ferret. Retrieved 14 June 2018.
  3. ^ Jump up to: a b c "WGSBN Bulletin Archive". Working Group Small Body Nomenclature. 14 May 2021. Retrieved 16 May 2021. (Bulletin #1)
  4. ^ Jump up to: a b c d "JPL Small-Body Database Browser: 15440 (1998 WX4)" (2018-05-20 last obs.). Jet Propulsion Laboratory. Retrieved 14 June 2018.
  5. ^ Jump up to: a b c d e f g h i "LCDB Data for (15440)". Asteroid Lightcurve Database (LCDB). Retrieved 14 June 2018.
  6. ^ "List of Jupiter Trojans". Minor Planet Center. 30 May 2018. Retrieved 14 June 2018.
  7. ^ Jump up to: a b c "Asteroid (15440) 1998 WX4 – Proper elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 5 June 2018.
  8. ^ 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)
  9. ^ Jump up to: a b c Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 15 June 2018.
  10. ^ Jump up to: a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
  11. ^ Jump up to: a b c Stephens, Robert D.; Warner, Brian D. (October 2017). "Lightcurve Analysis of L4 Trojan Asteroids at the Center for Solar System Studies 2017 April-June". The Minor Planet Bulletin. 44 (4): 312–316. Bibcode:2017MPBu...44..312S. ISSN 1052-8091.
  12. ^ 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.
  13. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 14 June 2018.
  14. ^ 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.
  15. ^ 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.

External links[]

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