Aubrite

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Aubrite
  Group  
Cumberland Falls meteorite.jpg
Cumberland Falls, an aubrite
Type Achondrite
Class Asteroidal achondrite or enstatite achondrite
Parent body Possibly (3103) Eger
Shallowater meteorite.jpg
Shallowater meteorite, an aubrite

Aubrites are a group of meteorites named for Aubres, [1] a small achondrite meteorite that fell in 1836 in Aubres near Nyons, France. They are primarily composed of the orthopyroxene enstatite and are often called enstatite achondrites. Their igneous origin separates them from primitive enstatite achondrites and means they originated in an asteroid.

Contents

Aubrites are typically light-colored with a brownish fusion crust. Most aubrites are heavily brecciated; they are often said to look "lunar" in origin.

Aubrites are primarily composed of large white crystals of the Fe-poor, Mg-rich orthopyroxene, or enstatite, with minor phases of olivine, nickel-iron metal, and troilite, indicating a magmatic formation under extremely reducing conditions. The severe brecciation 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 E-type asteroids of the Nysa family. A small near-Earth object, 3103 Eger, is also often suggested as the parent body of the aubrites. [2]

It has been suggested that aubrites may originate from the planet Mercury. [1] [3]

See also

Related Research Articles

<span class="mw-page-title-main">Meteorite</span> Solid debris from outer space that hits a planetary surface

A meteorite is a rock that originated in outer space and has fallen to the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star; astronomers call the brightest examples "bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater.

A V-type asteroid or Vestoid is an asteroid whose spectral type is that of 4 Vesta. Approximately 6% of main-belt asteroids are vestoids, with Vesta being by far the largest of them. They are relatively bright, and rather similar to the more common S-type asteroid, which are also made up of stony irons and ordinary chondrites, with V-types containing more pyroxene than S-types.

<span class="mw-page-title-main">Meteorite classification</span> Systems of grouping meteorites based on shared characteristics

In meteoritics, a meteorite classification system attempts to group similar meteorites and allows scientists to communicate with a standardized terminology when discussing them. Meteorites are classified according to a variety of characteristics, especially mineralogical, petrological, chemical, and isotopic properties.

<span class="mw-page-title-main">E-type asteroid</span>

E-type asteroids are asteroids thought to have enstatite (MgSiO3) achondrite surfaces. They form a large proportion of asteroids inward of the asteroid belt known as Hungaria asteroids, but rapidly become very rare as the asteroid belt proper is entered. Some are quite far from the inner edge of the asteroid belt, such as 64 Angelina. They are thought to have originated from the highly reduced mantle of a differentiated asteroid.

<span class="mw-page-title-main">Chondrite</span> Class of stony meteorites made of round grains

A chondrite is a stony (non-metallic) meteorite that has not been modified, by either melting or differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar System accreted to form primitive asteroids. Some such bodies that are captured in the planet's gravity well become the most common type of meteorite by arriving on a trajectory toward the planet's surface. Estimates for their contribution to the total meteorite population vary between 85.7% and 86.2%.

<span class="mw-page-title-main">44 Nysa</span> Main-belt asteroid

Nysa is a large and very bright main-belt asteroid, and the brightest member of the Nysian asteroid family. It is classified as a rare class E asteroid and is probably the largest of this type.

<span class="mw-page-title-main">Achondrite</span> Stony meteorite that does not contain chondrules

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. As a result, achondrites have distinct textures and mineralogies indicative of igneous processes.

Hungaria is a relatively small asteroid orbiting in the inner asteroid belt. It is an E-type (high-albedo) asteroid. It is the namesake of the Hungaria asteroids, which orbit the Sun on the inside of the 1:4 Kirkwood gap, standing out of the core of the asteroid belt.

<span class="mw-page-title-main">HED meteorite</span> Group of achondrite meteorites

HED meteorites are a clan (subgroup) of achondrite meteorites. HED stands for "howardite–eucrite–diogenite". These achondrites came from a differentiated parent body and experienced extensive igneous processing not much different from the magmatic rocks found on Earth and for this reason they closely resemble terrestrial igneous rocks.

<span class="mw-page-title-main">Eucrite</span> Achondritic stony meteorite

Eucrites are achondritic stony meteorites, many of which originate from the surface of the asteroid 4 Vesta and are part of the HED meteorite clan. They are the most common achondrite group with over 100 meteorites found.

<span class="mw-page-title-main">H chondrite</span> Type of meteorite

The H type ordinary chondrites are the most common type of meteorite, accounting for approximately 40% of all those catalogued, 46% of the ordinary chondrites, and 44% of all chondrites. The ordinary chondrites are thought to have originated from three parent asteroids, whose fragments make up the H chondrite, L chondrite and LL chondrite groups respectively.

<span class="mw-page-title-main">Ordinary chondrite</span> Class of stony meteorites

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<span class="mw-page-title-main">3103 Eger</span> Apollo asteroid

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 has an albedo of 0.64, making it a highly reflective asteroid.

The Hungaria asteroids, also known as the Hungaria group, are a dynamical group of asteroids in the asteroid belt which orbit the Sun with a semi-major axis between 1.78 and 2.00 astronomical units (AU). They are the innermost dense concentration of asteroids in the Solar System—the near-Earth asteroids are much more sparse—and derive their name from their largest member 434 Hungaria. The Hungaria group includes the Hungaria family, a collisional asteroid family which dominates its population.

<span class="mw-page-title-main">Zaklodzie meteorite</span> Meteorite found in Poland

The Zakłodzie meteorite is a stony-iron meteorite found in Poland in 1998. Its mass is 8.68 kilograms (19.1 lb). It is composed predominantly from enstatite and meteoric iron. Currently classified as an ungrouped enstatite achondrite its classification is still an ongoing scientific debate.

The Itqiy meteorite is an enstatite-rich stony-iron meteorite. It is classified as an enstatite chondrite of the EH group that was nearly melted and is therefore very unusual for that group. Other classifications have been proposed and are an ongoing scientific debate.

This is a glossary of terms used in meteoritics, the science of meteorites.

<span class="mw-page-title-main">Northwest Africa 7325</span>

Northwest Africa 7325, also known as NWA 7325, is a unique igneous meteorite which crystallized as a basalt on a large asteroid or planetesimal approximately 4.56 billion years ago. It is classified as an ungrouped achondrite, and is notable for its green fusion crust and high-magnesium/low-iron composition. It was purchased from anonymous finders in a marketplace in Erfoud, Morocco in April 2012. The original find was composed of 35 fragments with a combined weight of approximately 345 grams (12.2 oz), however many additional fragments with a total weight of over 1,100 grams (39 oz) were subsequently recovered.

Bunburra Rockhole is an anomalous basaltic achondritic meteorite. Originally classified as a eucrite, it was thought to belong to a group of meteorites that originated from the asteroid 4 Vesta, but has since been reclassified based on oxygen and chromium isotopic compositions. It was observed to fall on July 21, 2007, 04:43:56 local time, by the Desert Fireball Network (DFN). Two fragments weighing 150g and 174g were recovered by the DFN at 31°21.0′S, 129°11.4′E in the Nullarbor Desert region, South Australia in November of the same year. This is the first meteorite to be recovered using the Desert Fireball Network observatory.

<span class="nowrap">2024 BX<sub>1</sub></span> 2024 meteoroid

2024 BX1, previously known under its temporary designation Sar2736, was a metre-sized asteroid or meteoroid that entered Earth's atmosphere on 21 January 2024 00:33 UTC and disintegrated as a meteor over Berlin. It was discovered less than three hours before impact by Hungarian astronomer Krisztián Sárneczky at Konkoly Observatory's Piszkéstető Station in the Mátra Mountains, Hungary. The fireball was observed by the cameras of the AllSky7 and Fripon networks. 2024 BX1 is the eighth asteroid discovered before impacting Earth, and is Sárneczky's third discovery of an impacting asteroid. Before it impacted, 2024 BX1 was a near-Earth asteroid on an Earth-crossing Apollo-type orbit.

References

  1. 1 2 O'Callaghan, Jonathan (10 February 2024). "Fragments of Asteroid With Mystery Origin Are Found Outside Berlin - Astronomers tracked the entry of a small space rock into Earth's atmosphere, and then meteorite hunters made an unexpected discovery". The New York Times . Archived from the original on 10 February 2024. Retrieved 10 February 2024.
  2. Gaffey, Michael J.; Reed, Kevin L.; Kelley, Michael S. (November 1992). "Relationship of E-type Apollo asteroid 3103 (1982 BB) to the enstatite achondrite meteorites and the Hungaria asteroids". Icarus. 100 (1): 95–109. Bibcode:1992Icar..100...95G. doi:10.1016/0019-1035(92)90021-X . Retrieved 14 May 2021.
  3. O'Callaghan, Jonathan (23 May 2022). "Shards of the Planet Mercury May Be Hiding on Earth". The New York Times . Retrieved 14 February 2023.