Aubrite

{{Short description|Group of meteorites}} {{for|the album|Aubrite (album)}} {{Refimprove|date=March 2009}} {{Infobox meteorite subdivision |Subdivision = Group |Name = Aubrite |Alternative_names = |Image = Cumberland Falls meteorite.jpg |Image_caption = Cumberland Falls, an aubrite |Image_alt_text = |Compositional_type =  |Type = Achondrite |Class = Asteroidal achondrite or enstatite achondrite |Clan =  |Structural_classification = |Parent_body = Possibly (3103) Eger |Composition = |Petrologic_type = |Number_of_specimens = |TKW =  |Image2 = Shallowater meteorite.jpg |Image2_caption = Shallowater meteorite, an aubrite |Image2_alt_text = }} thumb|354x354px|'''Fragment of the Aubres meteorite observed under a microscope at 40x magnification.''' '''Aubrites''' are a group of meteorites named for Aubres,<ref name="NYT-20240210" /> 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.

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.<ref>{{cite journal |last1=Gaffey |first1=Michael J. |last2=Reed |first2=Kevin L. |last3=Kelley |first3=Michael S. |date=November 1992 |title=Relationship of E-type Apollo asteroid 3103 (1982 BB) to the enstatite achondrite meteorites and the Hungaria asteroids |journal=Icarus |volume=100 |issue=1 |pages=95–109 |doi=10.1016/0019-1035(92)90021-X |bibcode=1992Icar..100...95G |url=https://ui.adsabs.harvard.edu/abs/1992Icar..100...95G/abstract |access-date=14 May 2021}}</ref>

It has been suggested that aubrites may originate from the planet Mercury.<ref name="NYT-20240210">{{cite news |last=O'Callaghan |first=Jonathan |title=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. |url=https://www.nytimes.com/2024/02/10/science/aubrite-asteroid-meteorite-berlin.html |date=10 February 2024 |work=The New York Times |url-status=live |archiveurl=https://archive.today/20240210183139/https://www.nytimes.com/2024/02/10/science/aubrite-asteroid-meteorite-berlin.html |archivedate=10 February 2024 |accessdate=10 February 2024 }}</ref><ref>{{cite web |last=O'Callaghan |first=Jonathan |date=23 May 2022 |title=Shards of the Planet Mercury May Be Hiding on Earth |url=https://www.nytimes.com/2022/05/23/science/mercury-meteorites-aubrites.html |website=The New York Times |access-date=14 February 2023}}</ref>

The aubrite 2024 BX<sub>1</sub> might on the other hand originate from the Hungaria family.<ref name="Cantillo2024">{{Cite journal |last1=Cantillo |first1=David C. |last2=Ridenhour |first2=Kaycee I. |last3=Battle |first3=Adam |last4=Joyce |first4=Thomas |last5=Nunez Breceda |first5=Juliana |last6=Pearson |first6=Neil |last7=Reddy |first7=Vishnu |date=2024-06-01 |title=Laboratory Spectral Characterization of Ribbeck Aubrite: Meteorite Sample of Earth-impacting Near-Earth Asteroid 2024 BX1 |journal=The Planetary Science Journal |volume=5 |issue=6 |pages=138 |bibcode=2024PSJ.....5..138C |doi=10.3847/PSJ/ad4885 |issn=2632-3338 |doi-access=free}}</ref><ref name="Bischoff2024">{{Cite journal |last1=Bischoff |first1=Addi |last2=Patzek |first2=Markus |last3=Barrat |first3=Jean-Alix |last4=Berndt |first4=Jasper |last5=Busemann |first5=Henner |last6=Degering |first6=Detlev |last7=Di Rocco |first7=Tommaso |last8=Ek |first8=Mattias |last9=Harries |first9=Dennis |last10=Godinho |first10=Jose R. A. |last11=Heinlein |first11=Dieter |last12=Kriele |first12=Armin |last13=Krietsch |first13=Daniela |last14=Maden |first14=Colin |last15=Marchhart |first15=Oscar |date=2024-07-31 |title=Cosmic pears from the Havelland (Germany): Ribbeck, the twelfth recorded aubrite fall in history |url=https://onlinelibrary.wiley.com/doi/10.1111/maps.14245 |journal=Meteoritics & Planetary Science |language=en |doi=10.1111/maps.14245 |issn=1086-9379|doi-access=free }}</ref> Its spectrum shows similarities to (434) Hungaria. The composition is however different when compared to (44) Nysa and (64) Angelina, ruling out a linkage.<ref name="Cantillo2024" /> Its orbit orientation does not agree with 3103 Eger, which rules out Eger as a direct origin. The spectrum is also not meaningfully similar when compared to Mercury.<ref name="Bischoff2024" />

== See also == * Glossary of meteoritics * 3103 Eger * 44 Nysa

==References== {{Reflist}}

== External links == {{Commons category|Aubrites}} * [http://www.daviddarling.info/encyclopedia/A/aubrite.html Encyclopedia − David Darling] * [http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1812.pdf Academic Report 2004 (PDF)] * [https://www.uni-muenster.de/imperia/md/content/planetologie/pdf/bischoff/mess_ii_endversion.pdf Academic Report 2006 (PDF)]

Category:Asteroidal achondrites