Thule, minor planet designation: 279 Thule, is a large asteroid from the outer

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, c ...

. It is classified as a

D-type asteroid D-type asteroids have a very low albedo and a featureless reddish spectrum. It has been suggested that they have a composition of organic-rich silicates, carbon and anhydrous silicates, possibly with water ice in their interiors. D-type asteroids ...

and is probably composed of organic-rich silicates,

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

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 25 October 1888 in

Vienna en, Viennese , iso_code = AT-9 , registration_plate = W , postal_code_type = Postal code , postal_code = , timezone = CET , utc_offset = +1 , timezone_DST ...

and was named after the ultimate northern land of

Thule Thule ( grc-gre, Θούλη, Thoúlē; la, Thūlē) is the most northerly location mentioned in ancient Greek and Roman literature and cartography. Modern interpretations have included Orkney, Shetland, northern Scotland, the island of Saar ...

Thule asteroids

Thule was the first discovered member of the ''Thule dynamical group'', which as of 2008 is known to consist of three objects: 279 Thule, , and . The orbits of these bodies are unusual. They orbit in the outermost edge of the asteroid belt in a 4:3

orbital resonance In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relationsh ...

with

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

, 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 gap A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids. They correspond to the locations of orbital resonances with Jupiter. For example, there a ...

s in the more inner parts of the asteroid belt.

References

External links

* * Thule asteroids Background asteroids

D-type asteroids (Tholen) X-type asteroids (SMASS) 18881025 {{beltasteroid-stub