| Minorplanet: | yes |
| 12444 Prothoon | |
| Background: |
|
| Discovered: | 15 April 1996 |
| Mpc Name: | (12444) Prothoon |
| Adjective: | Prothoonian |
| Named After: | Προθόων Prothoōn |
| Mp Category: | Jupiter trojan |
| Epoch: | 23 March 2018 (JD 2458200.5) |
| Uncertainty: | 0 |
| Observation Arc: | 22.17 yr (8,096 d) |
| Perihelion: | 4.8680 AU |
| Semimajor: | 5.2443 AU |
| Eccentricity: | 0.0718 |
| Period: | 12.01 yr (4,387 d) |
| Mean Motion: | / day |
| Inclination: | 30.827° |
| Asc Node: | 213.23° |
| Arg Peri: | 64.656° |
| Jupiter Moid: | 0.3876 AU |
| Tisserand: | 2.7120 |
| Mean Diameter: | |
| Albedo: | |
| Abs Magnitude: | 9.8 9.9 10.10 |
12444 Prothoon is a large Jupiter trojan from the Trojan camp, approximately 64km (40miles) in diameter. It was discovered on 15 April 1996, by Belgian astronomer Eric Elst at the La Silla Observatory in northern Chile. The assumed C-type asteroid is one of the 60 largest Jupiter trojans and has a rotation period of 15.82 hours. It was named after Prothoon from Greek mythology.
Prothoon is a dark Jovian asteroid orbiting in the trailering Trojan camp at Jupiter's Lagrangian point, 60° behind on the Gas Giant's orbit in a 1:1 resonance (see Trojans in astronomy). This asteroid is not a member of any asteroid family but belongs to the Jovian background population. It orbits the Sun at a distance of 4.9–5.6 AU once every 12.01 years (4,387 days; semi-major axis of 5.24 AU). Its orbit has an eccentricity of 0.07 and an inclination of 31° with respect to the ecliptic. The body's observation arc begins with a precovery taken at La Silla in March 1996, one month prior to its official discovery observation.
Prothoon is an assumed C-type asteroid.
In August 2011, a rotational lightcurve of Prothoon was obtained from photometric observations by Robert Stephens at the Goat Mountain Astronomical Research Station in California. Lightcurve analysis gave a rotation period of 15.82 hours with a brightness amplitude of 0.20 magnitude .
According to the surveys carried out by the Japanese Akari satellite, the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, and the Infrared Astronomical Satellite IRAS, Prothoon measures between 62.41 and 64.31 kilometers in diameter and its surface has an albedo between 0.039 and 0.052.
The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0467 and a diameter of 64.41 kilometers based on an absolute magnitude of 9.9.
This minor planet was named from Greek mythology after the Trojan warrior Prothoon, who was killed by Teucer during the Trojan War. The official naming citation was published by the Minor Planet Center on 6 January 2003 .