7152 Euneus/juːˈniːəs/ is aJupiter trojan from theGreek camp, approximately 40 kilometers (25 miles) in diameter. It was discovered during the secondPalomar–Leiden Trojan survey in 1973, and later named afterEuneus from Greek mythology.^[1] The dark Jovianasteroid has arotation period of 9.7 hours and is likely spherical in shape.^[7]

Euneus was discovered on 19 September 1973, by Dutch astronomersIngrid andCornelis van Houten atLeiden, onphotographic plates taken byTom Gehrels at thePalomar Observatory in California. The body'sobservation arc begins with its official discovery observation.^[1]

While the discovery date aligns with the secondPalomar–Leiden Trojan survey,Euneus has not received a"T-2" prefixedsurvey 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'sSamuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory whereastrometry was carried out. The trio are credited with the discovery ofseveral thousand asteroids.^[9]

Thisminor planet was named afterEuneus, son ofJason andHypsipyle. He was the king ofLemnos and reprovisioned the Greek fleet with wine during theTrojan War.^[1] The official naming citation was published by theMinor Planet Center on 18 August 1997 (M.P.C. 30478).^[10]

Euneus is a darkJupiter trojan in a 1:1orbital resonance withJupiter. It is located in the leadingGreek camp at the Gas Giant'sL₄Lagrangian point, 60° ahead of its orbit(seeTrojans in astronomy).^[4] It is also a non-family asteroid in theJovian 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 aneccentricity of 0.06 and aninclination of 4° with respect to theecliptic.^[3]

Euneus is an assumed, carbonaceousC-type asteroid.^[7] Most Jupiter trojans areD-types, with the remainder being mostly C andP-type asteroids. It has a typicalV–I color index of 0.91 and aBR color of 1.24(also see table below).^[7]

In January 2013,Robert Stephens at theCenter for Solar System Studies attempted to obtain a rotationallightcurve ofEuneus fromphotometric observations. However, during three consecutive nights of observations, norotation period could be determined as the lightcurve's brightness did not vary by more than 0.01magnitude (U=n.a.).^[11]

In April 2015, follow-up observations by Stephens gave a period of9.73±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 nearpole-on during the 2013-opposition.^[7][8][a]

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

• Asteroid Lightcurve Database (LCDB), query form (infoArchived 16 December 2017 at theWayback Machine)
• Dictionary of Minor Planet Names, Google books
• Discovery Circumstances: Numbered Minor Planets (5001)-(10000) – Minor Planet Center
• Asteroid 7152 Euneus at the Small Bodies Data Ferret
• 7152 Euneus atAstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 7152 Euneus at theJPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Jupiter trojans (Greek camp)
• Discoveries by Cornelis Johannes van Houten
• Discoveries by Ingrid van Houten-Groeneveld
• Discoveries by Tom Gehrels
• Named minor planets
• Astronomical objects discovered in 1973

• CS1 maint: multiple names: authors list
• Articles with short description
• Short description is different from Wikidata
• Use dmy dates from June 2018
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