Ordinary chondrite

Ordinary chondrite
Ordinary chondrite NWA 869

The Ordinary chondrites (sometimes called the O chondrites) are a class of stony chondritic meteorites. They are by far the most numerous group and comprise about 87% of all finds[1]. Hence, they have been dubbed "ordinary".

It is suspected that they are not representative of typical asteroid parent bodies, but rather of a select few which are advantageously placed to send impact fragments to Earth-crossing orbits. Such positions are e.g. near Kirkwood gaps and/or secular resonances in the main asteroid belt. In fact, only the one rather insignificant asteroid 3628 Božněmcová has been identified to have a spectrum close to the ordinary chondrites.

A probable parent body of the H chondrites (comprising about 46% of the ordinary chondrites) is 6 Hebe, but its spectrum is dissimilar due to what is likely a metal impact melt component[2].

It is likely that the ordinary chondrites comprise a detailed sample of but a few select asteroids which happen to have been in the right place at the right time to send many fragments toward Earth at the present moment in solar system history. On the other hand, observations of 243 Ida by the Galileo spacecraft found weathering of Ida's surface, and the reflection spectra of freshly exposed parts of the surface resembled that of OC meteorites, while the older regions matched the spectra of common S-type asteroids.

The ordinary chondrites comprise three mineralogically and chemically distinct groupings. They differ in the amount of total iron, of iron metal and iron oxide in the silicates.

  • The H chondrites have the Highest total iron, high metal, but lower iron oxide (Fa) in the silicates;
  • The L chondrites have Lower total iron, lower metal, but higher iron oxide (Fa) in the silicates;
  • The LL chondrites have Low total iron and Low metal, but the highest iron oxide content (Fa) in the silicates.

See also


  1. ^ Natural History Museum, meteorite catalogue
  2. ^ M. J. Gaffey & S. L. Gilbert Asteroid 6 Hebe: The probable parent body of the H-Type ordinary chondrites and the IIE iron meteorites, Meteoritics & Planetary Science, Vol. 33, p. 1281 (1998)

External links

Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Chondrite — Not to be confused with Chondrodite. A specimen of the NWA 869 chondrite (type L4 6), showing chondrules and metal flakes Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They… …   Wikipedia

  • Chondrite de type H — Chondrite de type H5 Sud Maroc Les chondrites ordinaires de type H sont le type de météorite le plus courant. Elles constituent environ 40 % des météorites, 46 %des chondrites ordinaires et 44 % des chondrites[1]. Le nom vient de… …   Wikipédia en Français

  • Chondrite — Allende (Meteorit) L6 Chondrit Holbrook. Schnittfläche, helle Körner sind Metall. Höhe 5 cm. Chondrite bilden mit einem Anteil von etwa 86 Prozent die größte Klasse der …   Deutsch Wikipedia

  • chondrite — chondritic /kon drit ik/, adj. /kon druyt/, n. a stony meteorite containing chondrules. [1880 85; CHONDR + ITE1] * * * ▪ meteorite  in general, any stony meteorite characterized by the presence of chondrules. The only meteorites classified as… …   Universalium

  • LL chondrite — The LL chondrites are the least abundant group of the ordinary chondrites, accounting for about 10 11% of observed ordinary chondrite falls and 8 9% of all meteorite falls (see meteorite fall statistics).LL stands for Low (total) iron, Low metal …   Wikipedia

  • H chondrite — 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 the chondrites1. The name comes from their (H)igh iron abundance, with… …   Wikipedia

  • L chondrite — The L type ordinary chondrites are the second most common type of meteorite, accounting for approximately 35% of all those catalogued, and 40% of the ordinary chondrites. [ [http://internt.nhm.ac.uk/jdsml/research… …   Wikipedia

  • Gewöhnliche Chondrite — Der gewöhnliche Chondrit NWA 869 Gewöhnliche Chondrite sind die häufigsten Meteoriten. Sie enthalten kugelförmige Einschlüsse von Mineralen, die Chondren, die gewöhnlich aus Olivin und/oder Pyroxen bestehen. Die Chondren repräsentieren… …   Deutsch Wikipedia

  • meteorite — meteoritic /mee tee euh rit ik/, meteoritical, meteorital /mee tee euh ruyt l/, adj. /mee tee euh ruyt /, n. 1. a mass of stone or metal that has reached the earth from outer space; a fallen meteoroid. 2. a meteoroid. [1815 25; METEOR + ITE1] * * …   Universalium

  • Meteorite classification — The ultimate goal of meteorite classification is to group all meteorite specimens that share a common origin on a single, identifiable parent body. This could be a planet, asteroid, Moon, or other current Solar System object, or one that existed… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”