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The spectra of the V-type asteroids, or vestoids, are similar to that of 4 Vesta, by far the largest asteroid in this class (hence the name). Approximately 6% of main-belt asteroids are vestoids. A large proportion have orbital elements similar to those of 4 Vesta, either close enough to be part of the Vesta family, or having similar eccentricities and inclinations but with a semi-major axis lying between about 2.18 AU and the 3:1 Kirkwood gap at 2.50 AU. This suggests that most or all of them originated as fragments of Vesta's crust, possibly blasted out by a single very large impact at some point in its history. The enormous southern-hemisphere crater on Vesta, Rheasilvia, is the prime candidate for the impact site. The V-type asteroids are moderately bright, and rather similar to the more common S-type, which are also made up of stony irons and ordinary chondrites. This rather rare type of asteroid contains more pyroxene than the S-type. The electromagnetic spectrum has a very strong absorption feature longward of 0.75 μm, another feature around 1 μm and is very red shortwards of 0.7 µm. The visible wavelength spectrum of the V-type asteroids (including 4 Vesta itself) is similar to the spectra of basaltic achondrite HED meteorites. A J-type has been suggested for asteroids having a particularly strong 1 μm absorption band similar to diogenite meteorites, likely being derived from deeper parts of the crust of 4 Vesta. == Distribution == The vast majority of V-type asteroids are members of the Vesta family along with Vesta itself. There are some Mars-crossers such as 9969 Braille, and some Near-Earth objects like 3908 Nyx. There is also a scattered group of objects in the general vicinity of the Vesta family but not part of it. These include: * 809 Lundia — Orbits within the Flora family region * 956 Elisa * 1459 Magnya — Orbits in the outer asteroid belt, too far from Vesta to be genetically related. May be the remains of a different ancient differentiated body that was shattered long ago. * 2113 Ehrdni * 2442 Corbett * 2566 Kirghizia * 2579 Spartacus — Contains a significant portion of olivine, which may indicate origin deeper within Vesta than other V-types. * 2640 Hallstrom * 2653 Principia * 2704 Julian Loewe * 2763 Jeans * 2795 Lepage * 2851 Harbin * 2912 Lapalma * 3849 Incidentia * 3850 Peltier — Orbits within the Flora family region * 3869 Norton * 4188 Kitezh * 4278 Harvey — Member of Baptistina family. * 4434 Nikulin * 4796 Lewis * 4977 Rauthgundis * 5379 Abehiroshi 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「V-type asteroid」の詳細全文を読む スポンサード リンク
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