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7152 Euneus

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7152 Euneus
Discovery [1]
Discovered byC. J. van Houten
I. van Houten-G.
Tom Gehrels
Discovery sitePalomar Obs.
Discovery date19 September 1973
Designations
(7152) Euneus
Pronunciation/jˈnəs/[2]
Named after
Euneus (Greek mythology)[1]
1973 SH1 · 1990 DG3
Jupiter trojan[1][3]
Greek[4] · background[5]
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc44.67 yr (16,315 d)
Aphelion5.4812 AU
Perihelion4.8304 AU
5.1558 AU
Eccentricity0.0631
11.71 yr (4,276 d)
227.90°
0° 5m 3.12s / day
Inclination3.7122°
113.04°
306.16°
Jupiter MOID0.1553 AU
TJupiter2.9920
Physical characteristics
39.77±0.20 km[6]
48.48 km (calculated)[7]
9.73±0.02 h[8][a]
0.057 (assumed)[7]
0.093±0.022[6]
C(assumed)[7]
V–I = 0.910±0.041[7]
BR = 1.240±0.086[7]
10.20[3][6]
10.3[1][7]

7152 Euneus /jˈnəs/ is a Jupiter trojan from the Greek camp, approximately 40 kilometers (25 miles) in diameter. It was discovered during the second Palomar–Leiden Trojan survey in 1973, and later named after Euneus from Greek mythology.[1] The dark Jovian asteroid has a rotation period of 9.7 hours and is likely spherical in shape.[7]

Discovery

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Euneus was discovered on 19 September 1973, by Dutch astronomers Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Tom Gehrels at the Palomar Observatory in California. The body's observation arc begins with its official discovery observation.[1]

Palomar–Leiden Trojan survey

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While the discovery date aligns with the second Palomar–Leiden Trojan survey, Euneus has not received a "T-2" prefixed survey designation, which was assigned to the discoveries made by the fruitful collaboration between the Palomar and Leiden observatories in the 1960s and 1970s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of several thousand asteroids.[9]

Naming

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This minor planet was named after Euneus, son of Jason and Hypsipyle. He was the king of Lemnos and reprovisioned the Greek fleet with wine during the Trojan War.[1] The official naming citation was published by the Minor Planet Center on 18 August 1997 (M.P.C. 30478).[10]

Orbit and classification

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Euneus 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 of its orbit (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 4.8–5.5 AU once every 11 years and 9 months (4,276 days; semi-major axis of 5.16 AU). Its orbit has an eccentricity of 0.06 and an inclination of 4° with respect to the ecliptic.[3]

Physical characteristics

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Euneus is an assumed, carbonaceous C-type asteroid.[7] Most Jupiter trojans are D-types, with the remainder being mostly C and P-type asteroids. It has a typical V–I color index of 0.91 and a BR color of 1.24 (also see table below).[7]

Rotation period

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In January 2013, Robert Stephens at the Center for Solar System Studies attempted to obtain a rotational lightcurve of Euneus from photometric observations. However, during three consecutive nights of observations, no rotation period could be determined as the lightcurve's brightness did not vary by more than 0.01 magnitude (U=n.a.).[11]

In April 2015, follow-up observations by Stephens gave a period of 9.73±0.02 hours, still with a low brightness amplitude of 0.09 magnitude, indicating that the body is likely of spherical shape (U=2). Stephens also reanalyzed his data from 2013 using the newly obtained period which still resulted in an essentially flat lightcurve. He concluded that the body was possibly observed near pole-on during the 2013-opposition.[7][8][a]

Diameter and albedo

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According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Euneus measures 39.77 kilometers in diameter and its surface has an albedo of 0.093,[6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 48.48 kilometers based on an absolute magnitude of 10.3.[7]

100+ largest Jupiter trojans

Notes

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  1. ^ Jump up to: a b Lightcurve plots of (7152) Euneus from Jan 2013 and Apr 2015 by Robert Stephens at the Center for Solar System Studies (U81). Quality code is n.a./2 (lightcurve rating at CS3). Summary figures at the LCDB and CS3.

References

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  1. ^ Jump up to: a b c d e f g "7152 Euneus (1973 SH1)". Minor Planet Center. Retrieved 28 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: 7152 Euneus (1973 SH1)" (2018-05-21 last obs.). Jet Propulsion Laboratory. Retrieved 28 June 2018.
  4. ^ Jump up to: a b "List of Jupiter Trojans". Minor Planet Center. 1 June 2018. Retrieved 28 June 2018.
  5. ^ Jump up to: a b "Asteroid (7152) Euneus – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 28 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. Retrieved 28 June 2018. (online catalog)
  7. ^ Jump up to: a b c d e f g h i j k "LCDB Data for (7152) Euneus". Asteroid Lightcurve Database (LCDB). Retrieved 28 June 2018.
  8. ^ Jump up to: a b 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. Retrieved 28 June 2018.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ "Minor Planet Discoverers". Minor Planet Center. 31 May 2018. Retrieved 28 June 2018.
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 28 June 2018.
  11. ^ 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. Retrieved 28 June 2018.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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