V-type asteroid

A V-type (volcanic-type) asteroid, or Vestoid, is an asteroid whose spectral type is that of 4 Vesta. Approximately 6% of main-belt asteroids are vestoids,[citation needed] with Vesta being by far the largest of them. They are relatively bright, and rather similar to the more common S-type asteroid, which are also made up of stony irons and ordinary chondrites, with V-types containing more pyroxene than S-types.

A large proportion of vestoids have orbital elements similar to those of 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 they originated as fragments of Vesta's crust. There seem to be two populations of Vestoids, one created 2 billion years ago and the other 1 billion years ago, coming respectively from the enormous southern-hemisphere craters Veneneia and Rheasilvia. Fragments that ended up in the 3:1 Jupiter resonance were perturbed out of the Kirkwood gap and some fragments eventually hit the earth as HED meteorites.

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.[citation needed] 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 Vestoid 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

V-type near-Earth asteroids

2006 VV2 2008 BT18

V-type asteroid

Bron en licentie