Astronomy:Brachinite
Brachinites are a group of meteorites that are classified either as primitive achondrites or as asteroidal achondrites. Like all primitive achondrites, they have similarities with chondrites and achondrites. Brachinites contain 74 to 98% (volume) olivine.
Naming and history
Brachinites are named after the Brachina meteorite, the type specimen of this group, which in turn is named after Brachina, South Australia.[1]
Description
Brachinites consist almost entirely of olivine (74 to 98% by volume). Other minerals include plagioclase (6.7 to 12.9%), iron sulfides (1.8 to 4.0%), clinopyroxene (1.5 to 8.2%) and orthopyroxene (0 to 2.4%). Trace minerals include phosphates and meteoritic iron. The only deviation from chondrites is the very high olivine/orthopyroxene ratio.[2]
Specimens
As of 2022, there were 56 meteorites classified as brachinites.[3] A notable example is the type specimen, the Brachina meteorite.
See also
References
- ↑ "Brachina". Meteoritical Society. http://www.lpi.usra.edu/meteor/metbull.php?sea=Brachinite&sfor=types&ants=&falls=&valids=&stype=exact&lrec=2000&map=ge&browse=&country=All&srt=name&categ=All&mblist=All&rect=&phot=&snew=0&pnt=Normal%20table&code=5127.
- ↑ Nehru, C. E.; M. Prinz; M. K. Weisberg; M. Ebihara; R. N. Clayton; T. K. Mayeda (1992). "Brachinites: A New Primitive Achondrite Group". Meteoritics 27 (3): 267.
- ↑ "Meteoritical Bulletin Database". Meteoritical Society. http://www.lpi.usra.edu/meteor/metbull.php.
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