Discovered by F. Börngen MPC designation 3540 Protesilaos Absolute magnitude 9 Discoverer Freimut Börngen | Discovery date 27 October 1973 Discovered 27 October 1973 Orbits Sun Asteroid group Jupiter trojan | |
Pronunciation ˌproʊtəsᵻˈleɪəs
(proe'-tə-sə-lay'-əs) Named after Protesilaus
(Greek mythology) Alternative names 1973 UF5 · 1978 GJ2
1985 VO1 Discovery site Karl Schwarzschild Observatory People also search for 3391 Sinon, 2759 Idomeneus | ||
3540 Protesilaos (proe'-TƏ-sə-LAY'-əs), provisional designation 1973 UF5, is a carbonaceous Jupiter trojan from the Greek camp, approximately 80 kilometers in diameter. It was discovered on 27 October 1973, by German astronomer Freimut Börngen at the Karl Schwarzschild Observatory in Tautenburg, Germany.
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 1 month (4,423 days). Its orbit has an eccentricity of 0.12 and an inclination of 23° with respect to the ecliptic. The first precovery was taken at Palomar Observatory in 1953, extending the asteroid's observation arc by 20 years prior to its discovery.
Two rotational light-curves were obtained by astronomer Stefano Mottola at DLR Institute for Planetary Research (1989), and by Linda French using the Cerro Tololo Inter-American Observatory in Chile (2010). The first light-curve gave a rotation period of 8.945 hours with a brightness amplitude of 0.13 in magnitude (U=2). The second light-curve showed a nearly identical period of 7000894999999999999♠8.95±0.02 hours with no brightness variation given (U=2).
According to the surveys carried out by the Japanese Akari satellite, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the Trojan asteroid has a concurring albedo of 0.062, but measures 87.7 and 70.2 kilometers in diameter, respectively. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057, and calculates a diameter of 76.8 kilometers.
The minor planet is named after the hero Protesilaus from Greek mythology. In the Trojan War, he was the first Greek to set foot on the shores of Troy. He was later killed by the Trojan Aeneas, after whom one of the largest Jupiter trojans, 1172 Äneas, is named. Another Jupiter trojan, 13062 Podarkes, is named after his brother Podarkes. Naming citation was published on 14 April 1987 (M.P.C. 11751).