V-type asteroid

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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).

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 is the prime candidate for the impact site ^[1].

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 ^[2], likely being derived from deeper parts of the crust of 4 Vesta.

[edit] 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^[3]:

809 Lundia Orbits within the Flora family region
956 Elisa
1459 Magnya Orbits in the outer main 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 Orbits within the Flora family region
4434 Nikulin
4796 Lewis
4977 Rauthgundis
5379 Abehiroshi

[edit] References

^ S. J. Bus and R. P. Binzel (2002). "Phase II of the Small Main-belt Asteroid Spectroscopy Survey: A feature-based taxonomy". Icarus 158: 146.
^ R. P. Binzel and S. Xu (1993). "Chips off of asteroid 4 Vesta: Evidence for the parent body of basaltic achondrite meteorites". Science 260: 186.
^ V. Carruba et al (2005). "On the V-type asteroids outside the Vesta family". Astronomy & Astrophysics 441: 819.