| Minorplanet: | yes |
| Background: |
|
| 911 Agamemnon | |
| Discovery Ref: |   |
| Discovered: | 19 March 1919 |
| Mpc Name: | (911) Agamemnon |
| Alt Names: | 1919 FD1937 QD |
| Pronounced: | [1] |
| Adjectives: | Agamemnonian [2] |
| Named After: | Agamemnon  |
| Mp Category: | Jupiter trojan  |
| Orbit Ref: |   |
| Epoch: | 23 March 2018 (JD 2458200.5) |
| Uncertainty: | 0 |
| Observation Arc: | 97.93 yr (35,770 d) |
| Perihelion: | 4.9300 AU |
| Semimajor: | 5.2766 AU |
| Eccentricity: | 0.0657 |
| Period: | 12.12 yr (4,427 d) |
| Mean Motion: | / day |
| Inclination: | 21.763° |
| Asc Node: | 338.01° |
| Arg Peri: | 80.874° |
| Satellites: | 1 |
| Jupiter Moid: | 0.1064 AU |
| Tisserand: | 2.8530 |
| Mean Diameter: | |
| Rotation: | |
| Albedo: | |
| Abs Magnitude: | 7.89 8.27 |
911 Agamemnon, provisional designation , is a large Jupiter trojan and a suspected binary asteroid from the Greek camp, approximately 168km (104miles) in diameter. It was discovered on 19 March 1919, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany. The dark D-type asteroid is one of the largest Jupiter trojans and has a rotation period of 6.6 hours. It is named after the Greek King Agamemnon, a main character of the Iliad.
Agamemnon is a dark Jovian asteroid orbiting in the Greek camp at Jupiter's leading Lagrangian point, 60° ahead of its orbit in a 1:1 resonance . It is also a non-family asteroid in the Jovian background population.
It orbits the Sun at a distance of 4.9–5.6 AU once every 12 years and 1 month (4,427 days; semi-major axis of 5.28 AU). Its orbit has an eccentricity of 0.07 and an inclination of 22° with respect to the ecliptic. The body's observation arc begins at Heidelberg in October 1927, more than 8 years after its official discovery observation.
In the Tholen classification, Agamemnon is a dark D-type asteroid. It has also been characterized as a D-type in both the Tholen- and SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2).
Photometric observations of this asteroid during 1997 were used to build a lightcurve showing a rotation period of hours with a brightness variation of magnitude. A 2009 study yielded a period of hours, in reasonable agreement with the previous result.
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Agamemnon measures between 131.04 and 185.30 kilometers in diameter, based on a common absolute magnitude of 7.89 and a surface albedo between 0.037 and 0.072. A concurring diameter estimate of kilometers from an occultation event (see below) has also been obtained. The Collaborative Asteroid Lightcurve Link agrees with the results obtained by IRAS, that is, an albedo of 0.0444 and a diameter of 166.66 kilometers based on an absolute magnitude of 7.89.
A 2012 stellar occultation produced a 2D shape model of roughly (with an irregular, skewed outline) and are suggestive of Agamemnon to have a satellite of approximately kilometers in diameter orbiting at from the primary's center.
This minor planet named from Greek mythology after King Agamemnon, the leader of the Greeks in the Trojan War. He is a main character of Homer's Iliad. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 .