Aubrite
Encyclopedia
Aubrites are meteorite
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...

s named for Aubres, a small achondrite meteorite that fell near Nyons
Nyons
Nyons is a commune in the Drôme department in southeastern France.-History:Nyons was settled in the 6th century BC as Nyrax by a Gallic tribe, probably the Segusiavi or the Sequani...

, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, in 1836. They are primarily composed of the orthopyroxene enstatite
Enstatite
Enstatite is the magnesium endmember of the pyroxene silicate mineral series enstatite - ferrosilite . The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and metamorphic rocks...

, and are often called enstatite achondrite
Achondrite
An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies...

s. Their igneous origin separates them from primitive enstatite achondrites and means they originated in an asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

.

Aubrites are typically light-colored, and with a brownish fusion crust. Most aubrites are heavily brecciated. It's often said that they look "lunar" in origin.

Aubrites are primarily composed of large white crystals of the Fe-poor, Mg-rich orthopyroxene, or enstatite. Around this matrix, they have minor phases of olivine, nickel-iron metal, troilite, which indicate a magmatic formation under extremely reducing conditions. The severe brecciation
Breccia
Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix, that can be either similar to or different from the composition of the fragments....

 of most aubrites attests to a violent history for their parent body. Since some aubrites contain chondritic xenoliths it is likely that the aubrite parent body collided with an asteroid of “F-chondritic” composition.

Comparisons of aubrite spectra to the spectra of asteroids have revealed striking similarities between the aubrite group and the main belt Nysian asteroid family. A small member of this asteroid family, 3103 Eger
3103 Eger
3103 Eger is an Apollo and Mars-crosser asteroid that was discovered in 1982, by Miklós Lovas. It was named after the city of Eger, Hungary.It makes eight approaches to Earth less than in the 20th and 21st centuries. The last close approach was in August 2006 at...

, exhibits a near-Earth orbit, and is very likely the parent body of the aubrites.
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