.png)
E-type (enstatite achondrite–type) asteroids areasteroids thought to haveenstatite (MgSiO3)achondrite surfaces. They form a large proportion of asteroids inward of theasteroid belt known asHungaria asteroids,[1] 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 as64 Angelina. They are thought to have originated from the highly reduced mantle of a differentiated asteroid.
E-type asteroids have a highalbedo (0.3 or higher), which distinguishes them from the more commonM-typeasteroids. Theirspectrum is featureless flat to reddish. Probably because they originated from the edge of a larger parent body rather than a core, E-types are all small, with only three (44 Nysa,55 Pandora,64 Angelina) having diameters above 50 kilometres and no others above 25 kilometers (the biggest three also orbit atypically far, c. 3 AU, from the Sun).Aubrites (enstatite achondrite meteorites) are believed to come from E-type asteroids,[2] because Aubrites could be linked to the E-type asteroid3103 Eger.[3]
This grouping may be related to theXe-type of theSMASS classification.
The E-type asteroids of the Hungaria family are thought to be the remains of the hypotheticalE-belt asteroid population.[4] The dispersal of most of that hypothetical E-Belt might have been caused by theoutward migration of thegas giants of theSolar System according to simulations done under theNice model – and these dispersed E-Belt asteroids might in turn have been the impactors of theLate Heavy Bombardment.
On September 5, 2008, ESA's robotic spaceprobeRosetta visited the E-type asteroid2867 Šteins.[5] Spectral data from the spacecraft confirmed the asteroid was composed mainly of iron-poor minerals such asenstatite (magnesium-rich pyroxene),forsterite (magnesium-rich olivine) andfeldspar.
| Main | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Distribution |
| ||||||||
| Classification |
| ||||||||
| Exploration | |||||||||
| Lists | |||||||||
| Related | |||||||||
 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "E-type asteroid" – news ·newspapers ·books ·scholar ·JSTOR(September 2008) (Learn how and when to remove this message) |
