279 Thule

279 Thule

Discovery
Discovered by	Johann Palisa
Discovery date	October 25, 1888
Designations
Alternative names	1927 EC, 1954 FF, A920 GA, A923 RA
Minor planet category	Asteroid belt (Thule)
Orbital characteristics
Epoch 27 August 2011 (JD 2455800.5)
Aphelion	4.3122281 AU
Perihelion	4.2329299 AU
Semi-major axis	4.2725790 AU
Eccentricity	0.0092799
Orbital period	8.8316810 a (3225.7715 d)
Mean anomaly	182.9163°
Inclination	2.33789°
Longitude of ascending node	73.6201°
Argument of perihelion	82.8223°
Physical characteristics
Dimensions	126.6 ± 3.7 km (IRAS)
Rotation period	15.96 h
Albedo	0.041
Temperature	133 K
Spectral type	B−V=0.75 U−B=0.32 D (Tholen) X (SMASSII)
Absolute magnitude (H)	8.57

279 Thule (/ˈθjuːliː/ THEW-lee) is a large asteroid from the asteroid belt. It is classified as a D-type asteroid and is probably composed of organic-rich silicates, carbon and anhydrous silicates. Thule was the first asteroid discovered with a semi-major axis greater than 4 AU. It was discovered by Johann Palisa on October 25, 1888 in Vienna and was named aptly after the ultimate northern land of Thule.

Thule asteroids

See also: Minor-planet groups out to Jupiter

Thule was the first discovered member of the Thule dynamical group, which as of 2008 is known to consist of three objects: 279 Thule, (186024) 2001 QG₂₀₇, and (185290) 2006 UB₂₁₉. The orbits of these bodies are unusual. They orbit in the outermost edge of the asteroid belt in a 4:3 orbital resonance with Jupiter, the result of the periodic force Jupiter exerts on a body with Thule's orbital period, in the same way (though with the reverse effect) as the Kirkwood gaps in the more inner parts of the asteroid belt.

External links

• Orbital simulation from JPL (Java) / Horizons Ephemeris