A V-type (volcanic-type) asteroid, or Vestoid, is an

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

whose

spectral type In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

is that of

4 Vesta Vesta (minor-planet designation: 4 Vesta) is one of the largest objects in the asteroid belt, with a mean diameter of . It was discovered by the German astronomer Heinrich Wilhelm Matthias Olbers on 29 March 1807 and is named after Vesta (mytho ...

. Approximately 6% of

main-belt asteroid The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...

s are vestoids, with Vesta being by far the largest of them. They are relatively bright, and rather similar to the more common

S-type asteroid S-type (stony-type or silicaceous-type) asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are ...

, which are also made up of stony

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

s and ordinary

chondrite A chondrite is a stony (non-metallic) meteorite that has not been modified by either melting or planetary differentiation, differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar Syste ...

s, with V-types containing more

pyroxene The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron ( ...

than S-types. A large proportion of vestoids have

orbital elements Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same o ...

similar to those of Vesta, either close enough to be part of the

Vesta family The Vesta family (adj. ''Vestian''; ) is a family of asteroids. The cratering family is located in the inner asteroid belt in the vicinity of its namesake and principal body, 4 Vesta. It is one of the largest asteroid families with more tha ...

, or having similar eccentricities and

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

s but with a

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the longe ...

lying between about 2.18 AU and the 3:1

Kirkwood gap A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids. They correspond to the locations of orbital resonances with Jupiter. The gaps were first n ...

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 Veneneia is the second-largest impact crater on asteroid 4 Vesta, at 52°S latitude.

and

Rheasilvia Rheasilvia is the largest impact crater on the asteroid Vesta. It is in diameter, which is 90% the diameter of Vesta itself, and is 95% the mean diameter of Vesta, . However, the mean is affected by the crater itself. It is 89% the mean equ ...

. 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 meteorite HED meteorites are a clan (subgroup) of achondrite meteorites. HED stands for " howardite– eucrite– diogenite". These achondrites came from a differentiated parent body and experienced extensive igneous processing not much different from the ...

s. The

electromagnetic spectrum The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high ...

has a very strong absorption feature longward of 0.75

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

, 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

s. A J-type has been suggested for asteroids having a particularly strong 1 μm absorption band similar to

diogenite Diogenites are a group of the HED meteorite clan, a type of achondritic stony meteorites. Origin and composition Diogenites are currently believed to originate from deep within the crust of the asteroid 4 Vesta, and as such are part of the HED ...

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 9969 Braille, provisional designation , is an eccentric, rare-type and elongated asteroid from the innermost regions of the asteroid belt, classified as Mars-crosser and slow rotator, approximately 1–2 kilometers in diameter. It was discover ...

, and some

Near-Earth objects A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun (perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit aro ...

3908 Nyx 3908 Nyx is an Amor asteroid, Amor and Mars-crosser asteroid. It was discovered by Hans-Emil Schuster on August 6, 1980, and is named after Nyx (mythology), Nyx, the Greek mythology, Greek goddess of the night, after which Pluto's natural satel ...

. 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 809 Lundia is a small, binary, V-type asteroid orbiting within the Flora family in the main belt. It is named after Lund Observatory, Sweden. Characteristics Lundia orbits within the Flora family. However, its V-type spectrum indicates that it ...

— Orbits within the

Flora family The Flora family (''adj. Florian''; ; also known as the Ariadne family) is a prominent family of stony asteroids located in the inner region of the asteroid belt. It is one of the largest families with more than 13,000 known members, or approx ...

region *

956 Elisa 956 Elisa ('' prov. designation:'' ''or'' ) is a Flora asteroid from the inner regions of the asteroid belt, approximately in diameter. It was discovered on 8 August 1921, by German astronomer Karl Reinmuth at the Heidelberg Observatory. The V ...

1459 Magnya 1459 Magnya, provisional designation , is a basaltic, slightly elongated asteroid from the outer regions of the asteroid belt, approximately 20 kilometers in diameter. Discovered by Grigory Neujmin at the Simeiz Observatory in 1937, this backgro ...

— Orbits in the outer

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...

, 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 The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a com ...

, which may indicate origin deeper within Vestoid than other V-types. * 2640 Hallstrom *

2653 Principia __NOTOC__ Year 653 ( DCLIII) was a common year starting on Tuesday of the Julian calendar. The denomination 653 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe ...

* 2704 Julian Loewe * 2763 Jeans * 2795 Lepage * 2851 Harbin * 2912 Lapalma * 3849 Incidentia * 3850 Peltier — Orbits within the

region * 3869 Norton * 4188 Kitezh * 4278 Harvey — Member of Baptistina family. * 4434 Nikulin * 4796 Lewis * 4977 Rauthgundis * 5379 Abehiroshi

V-type near-Earth asteroids

References

{{DEFAULTSORT:V-Type Asteroid Asteroid spectral classes *

Distribution

V-type near-Earth asteroids

See also

References