V-type asteroid

{{Short description|Asteroids similar to the asteroid 4 Vesta}}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|date=January 2013}} 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.{{cite magazine|title=Two craters that launched 1000 meteorites|url=https://www.newscientist.com/article/dn21801|magazine=New Scientist|date=May 11, 2012}}{{cite journal | author= S. J. Bus | author2= R. P. Binzel | name-list-style= amp| title= Phase II of the Small Main-belt Asteroid Spectroscopy Survey: A feature-based taxonomy| journal= Icarus| date= 2002| volume= 158| issue= 1 | pages= 146| doi= 10.1006/icar.2002.6856| bibcode=2002Icar..158..146B| s2cid= 4880578 }} 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,{{cite journal | author= R. P. Binzel | author2= S. Xu | name-list-style= amp| title= Chips off of asteroid 4 Vesta: Evidence for the parent body of basaltic achondrite meteorites| journal= Science| date= 1993| volume= 260| pages= 186–91 | doi= 10.1126/science.260.5105.186| pmid= 17807177 | issue= 5105|bibcode = 1993Sci...260..186B }} likely being derived from deeper parts of the crust of 4 Vesta.