Discovery date 24 September 1960 Alternative names 2008 P-L · 1972 RB2 Absolute magnitude 9.3 Discovery site Palomar Observatory | MPC designation 1868 Thersites Discovered 24 September 1960 Orbits Sun Asteroid group Jupiter trojan | |
Discovered by C. J. van Houten
I. van Houten G.
T. Gehrels Pronunciation θərˈsaɪtiːz (thər-sye'-teez) Named after Thersites
(Greek mythology) Discoverers Tom Gehrels, Cornelis Johannes van Houten, Ingrid van Houten-Groeneveld People also search for 1869 Philoctetes, 3391 Sinon | ||
1868 Thersites (thər-SYE'-teez), provisional designation 2008 P-L, is a carbonaceous Jupiter trojan from the Greek camp, approximately 70 kilometers in diameter. It was discovered by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Dutch-American astronomer Tom Gehrels at the U.S. Palomar Observatory, California, on 24 September 1960. On the same day, the group discovered another Jupiter trojan, 1869 Philoctetes.
The dark C-type asteroid is orbiting in the leading Greek camp at Jupiter's L4 Lagrangian point, 60° ahead of its orbit (see Trojans in astronomy). It orbits the Sun at a distance of 4.7–5.9 AU once every 12 years and 3 months (4,480 days). Its orbit has an eccentricity of 0.11 and an inclination of 17° with respect to the ecliptic. The first precovery was taken at Palomar Observatory in 1954, extending the asteroid's observation arc by 6 years prior to its discovery.
In 1994, photometric observations of this asteroid were made by Stefano Mottola at ESO's La Silla Observatory, Chile, using the Dutch 0.9-metre Telescope. The observations were used to build a light-curve showing a rotation period of 7001104160000000000♠10.416±0.014 hours with a brightness variation of 6999140000000000000♠0.14±0.01 magnitude (U=2+). According to the space-based surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid's diameter measures 78.9 and 68.2 kilometers, respectively, with a low albedo of 0.055 for its surface. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057, and calculates a shorter diameter of 66.9 kilometers, based on an absolute magnitude of 9.6.
The provisional survey designation "P-L" stands for Palomar–Leiden, named after Palomar Observatory and Leiden Observatory, which collaborated on the fruitful Palomar–Leiden survey 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 Cornelis and Ingrid van Houten at Leiden Observatory, where astrometry was carried out. The trio are credited with the discovery of several thousand minor planets.
The Trojan asteroid is named from Greek mythology after Thersites, a Greek warrior who wanted to abandon Troy's siege during the Trojan War and head home. The given name also refers to the fact, that the asteroid was discovered farthest from the L4 Lagrangian point. Naming citation was published before November 1977 (M.P.C. 3826).