3708 Socus (provisional designation:1974 FV₁) is a largeJupiter trojan from theTrojan camp, approximately 77 kilometers (48 miles) in diameter. It was discovered on 21 March 1974, by staff members of theCerro El Roble Observatory owned and operated by the Department of Astronomy of theUniversity of Chile.^[1] The assumedC-type asteroid has arotation period of 6.55 hours.^[4] It was named afterSocus, a hero from Greek mythology, who was killed in battle by Odysseus.^[2]

Socus is a dark Jovianasteroid orbiting in the trailingTrojan camp at Jupiter'sL₅Lagrangian point, 60° behind its orbit in a1:1 resonance(seeTrojans in astronomy). It is also a non-family asteroid of theJovian background population.^[6][15]

It orbits the Sun at a distance of 4.4–6.0 AU once every 11 years and 11 months (4,353 days;semi-major axis of 5.22 AU). Its orbit has aneccentricity of 0.16 and aninclination of 13° with respect to theecliptic.^[3] The body'sobservation arc begins with aprecovery taken atLowell Observatory in November 1930, more than 43 years prior to its official discovery observation at Cerro El Roble.^[1]

Thisminor planet was numbered by theMinor Planet Center on 7 October 1987 (M.P.C. 12323).^[16] On 14 May 2021, the object was named afterSocus from Greek mythology by theWorking Group for Small Bodies Nomenclature (WGSBN). While defending his brother, Socus was killed by Odysseus, who taunted him as he died.^[2]

Until the asteroid received its name in May 2021, it had been the lowest-numbered unnamed minor planet for many years (there are more thanhalf a million numbered minor planets with more than20,000 of them being named). This contrasts with the neighboring asteroids3707 Schröter and3709 Polypoites, that were named in September 1993 and April 1988, respectively (M.P.C. 22499/12976).^[16] The asteroid4035 Thestor, the next-lowest numbered unnamed minor planet, was also named by the WGSBN in May 2021.

Socus is an assumed, carbonaceousC-type asteroid.^[4]

In February 1993, a rotationallightcurve ofSocus was obtained fromphotometric observations by Italian astronomersStefano Mottola and Mario Di Martino, using theESO 1-metre telescope at ESO'sLa Silla site, Chile. Lightcurve analysis gave arotation period of 6.553 hours with a brightness variation of 0.23magnitude (U=3).^[4][12]

In January 2015, and February 2016, observations byRobert Stevens and Daniel Coley at theCenter for Solar System Studies in California gave two concurring periods of6.520±0.003 and6.55±0.01 hours and an amplitude of 0.31 and 0.20 inmagnitude, respectively (U=3-/3).^{[4][10][11][a]}

According to the surveys carried out by the JapaneseAkari satellite, theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer, and the Infrared Astronomical SatelliteIRAS,Socus measures between 75.66 and 79.59 kilometers in diameter and its surface has analbedo between 0.053 and 0.59.^[7][8][9]

TheCollaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0531 and a diameter of 79.59 kilometers based on anabsolute magnitude of 9.3.^[4]

• Asteroid Lightcurve Database (LCDB), query form (infoArchived 16 December 2017 at theWayback Machine)
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 3708 Socus atAstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 3708 Socus at theJPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Jupiter trojans (Trojan camp)
• Discoveries by the University of Chile
• Named minor planets
• Astronomical objects discovered in 1974

• CS1 maint: multiple names: authors list
• Use dmy dates from May 2021
• Webarchive template wayback links