4722 Agelaos
4722 Agelaos is a Jupiter trojan from the Trojan camp, approximately in diameter. It was discovered during the third Palomar–Leiden Trojan survey at the Palomar Observatory in California in 1977. The Jovian asteroid has a rotation period of 18.4 hours and belongs to the [|90 largest Jupiter trojans]. It was named after Agelaus from Greek mythology.
Discovery
Agelaos was discovered on 16 October 1977, by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Dutch–American astronomer Tom Gehrels at the Palomar Observatory in California. The body's observation arc begins with its first observations at Palomar on 7 October 1977, just nine day prior to its official discovery observation.Palomar–Leiden survey
The survey designation "T-3" stands for the third Palomar–Leiden Trojan survey, named after the fruitful collaboration of the Palomar and Leiden Observatory in the 1960s and 1970s. Gehrels used Palomar's Samuel Oschin 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 asteroid discoveries.Orbit and classification
Agelaos is a dark Jovian asteroid in a 1:1 orbital resonance with Jupiter. It is located in the trailering Trojan camp at the Gas Giant's Lagrangian point, 60° behind its orbit. It is also a non-family asteroid of the Jovian background population.It orbits the Sun at a distance of 4.6–5.8 AU once every 11 years and 11 months. Its orbit has an eccentricity of 0.11 and an inclination of 9° with respect to the ecliptic.
Physical characteristics
Agelaos is an assumed, carbonaceous C-type asteroid. It has a V–I color index of 0.91, typical for most Jovian D-type asteroids, the dominant spectral type among the larger Jupiter trojans.Rotation period
In December 2002, a first rotational lightcurve of Agelaos was obtained from photometric observations over two consecutive nights by Italian astronomer Stefano Mottola with the 1.2-meter telescope at Calar Alto Observatory in Spain. Lightcurve analysis gave a rotation period of 18.61 hours with a brightness amplitude of 0.23 magnitude. Observations in the R-band by astronomers at the Palomar Transient Factory in October 2012 gave a period of 18.456 hours with an amplitude of 0.15 magnitude.The so-far best-rated lightcurve by Robert Stephens at the Center for Solar System Studies in Landers, California, gave a concurring period of and a brightness variation of 0.19.