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 2.18AU and the 3:1 Kirkwood gap at 2.50AU. 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.

V-type asteroids include 4 Vesta, many members of the Vesta family, 9969 Braille, 3908 Nyx, and some Near-Earth objects.

References

1. S. J. Bus and R. P. Binzel Phase II of the Small Main-belt Asteroid Spectroscopy Survey: A feature-based taxonomy, Icarus, Vol. 158, pp. 146 (2002).
2. R. P. Binzel and S. Xu Chips off of asteroid 4 Vesta: Evidence for the parent body of basaltic achondrite meteorites, Science, Vol. 260, 186 (1993).