V-type asteroid

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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.

Contents

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. [1] [2] 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, [3] 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: [4]

V-type near-Earth asteroids

V-type NEAS (or V-NEAs) are near-Earth asteroids with a V spectral type. Impacts of V-NEAs on the Earth, according to the known sample (data taken in 2016), occur once in about 12 million years and have the potential to cause disastrous effects on regional to global scale, producing craters as large as 30 km in diameter and releasing kinetic energy of as much as 3 Mt. This energy is almost 6 million times greater than the energy released during the Chelyabinsk event in 2013. Venus, Mars and the Moon will experience impacts with V-NEAs every 22 Myr, 125 Myr and 168 Myr, respectively. Two craters with confirmed basaltic impactor which fits with the impact rate found from V-type NEAs are the Strangways crater (24 km diameter) in Australia, the Nicholson crater (12.5 km diameter) in Canada. Some V-NEAs have orbits similar to that of the Bunburra Rockhole meteorite. [5]

See also

Related Research Articles

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An asteroid is a minor planet—an object that is neither a true planet nor an identified comet— that orbits within the inner Solar System. They are rocky, metallic, or icy bodies with no atmosphere, classified as C-type (carbonaceous), M-type (metallic), or S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across and larger than meteoroids, to Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies.

<span class="mw-page-title-main">4 Vesta</span> Second largest asteroid of the main asteroid belt

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<span class="mw-page-title-main">Asteroid belt</span> Region between the orbits of Mars and Jupiter

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 or minor planets. The identified objects are of many sizes, but much smaller than planets, and, on average, are about one million kilometers apart. This asteroid belt is also called the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System.

<span class="mw-page-title-main">S-type asteroid</span> Asteroid spectral type indicating stony composition

S-type asteroids are asteroids with a spectral type that is indicative of a siliceous mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are of this type, making it the second-most common after the carbonaceous C-type.

<span class="mw-page-title-main">M-type asteroid</span> Asteroid spectral type

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3494 Purple Mountain, provisional designation 1980 XW, is a bright Vestian asteroid and a formerly lost minor planet from the inner regions of the asteroid belt, approximately 6.5 kilometers in diameter. First observed in 1962, it was officially discovered on 7 December 1980, by Chinese astronomers at the Purple Mountain Observatory in Nanking, China, and later named in honor of the discovering observatory. The V-type asteroid has a rotation period of 5.9 hours.

<span class="mw-page-title-main">Achondrite</span> Stony meteorite that does not contain chondrules

An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies. As a result, achondrites have distinct textures and mineralogies indicative of igneous processes.

The Vesta family 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 than 15,000 known members and consists of mostly bright V-type asteroids, so-called "vestoids".

<span class="mw-page-title-main">Asteroid spectral types</span> Classification type of a class of astronomical objects

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J-type asteroids are asteroids with spectra similar to that of diogenite meteorites and so, presumably, to the deeper layers of the crust of 4 Vesta.

<span class="mw-page-title-main">HED meteorite</span> Group of achondrite meteorites

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<span class="mw-page-title-main">Flora family</span> Grouping of S-type asteroids

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<span class="mw-page-title-main">Baptistina family</span> Asteroid group

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<span class="mw-page-title-main">9951 Tyrannosaurus</span> Asteroid

9951 Tyrannosaurus, provisional designation 1990 VK5, is a stony Vestian asteroid from the inner regions of the asteroid belt, approximately 17 kilometers in diameter. It was discovered on 15 November 1990, by Belgian astronomer Eric Elst at ESO's La Silla Observatory in northern Chile. It was named after Tyrannosaurus, a genus of dinosaurs.

7794 Sanvito, provisional designation 1996 AD4, is a bright Vestian asteroid from the inner regions of the asteroid belt, approximately 4.6 kilometers (2.9 miles) in diameter. It was discovered on 15 January 1996, by Italian astronomers Ulisse Munari and Maura Tombelli at the Cima Ekar Observing Station in Tuscany, Italy. The likely V-type asteroid was named after Italian amateur astronomer Roberto di San Vito.

10244 Thüringer Wald, provisional designation 4668 P-L, is a Vestian asteroid from the inner regions of the asteroid belt, approximately 3.3 kilometers in diameter. It was discovered on 26 September 1960, by Ingrid and Cornelis van Houten at Leiden, and Tom Gehrels at Palomar Observatory in California, United States. The asteroid was named after the Thuringian Forest, a German mountain range.

<span class="mw-page-title-main">Rheasilvia</span> Impact crater on the surface of the asteroid 4 Vesta

Rheasilvia is the largest impact crater on the asteroid Vesta. It is 505 km (314 mi) in diameter, which is 90% the diameter of Vesta itself, and is 95% the mean diameter of Vesta, 529 km (329 mi). However, the mean is affected by the crater itself. It is 89% the mean equatorial diameter of 569 km (354 mi), making it one of the largest craters in the Solar System, and at 75°S latitude, covers most of the southern hemisphere. The peak in the center of the crater is 200 km (120 mi) in diameter, and rises 22.5 km from its base, making it one of the tallest mountains known in the Solar System.

This is a glossary of terms used in meteoritics, the science of meteorites.

Bunburra Rockhole is an anomalous basaltic achondritic meteorite. Originally classified as a eucrite, it was thought to belong to a group of meteorites that originated from the asteroid 4 Vesta, but has since been reclassified based on oxygen and chromium isotopic compositions. It was observed to fall on July 21, 2007, 04:43:56 local time, by the Desert Fireball Network (DFN). Two fragments weighing 150g and 174g were recovered by the DFN at 31°21.0′S, 129°11.4′E in the Nullarbor Desert region, South Australia in November of the same year. This is the first meteorite to be recovered using the Desert Fireball Network observatory.

<span class="mw-page-title-main">2018 LA</span>

2018 LA, also known as ZLAF9B2, was a small Apollo near-Earth asteroid 2.6–3.8 m (9–12 ft) in mean diameter that impacted the atmosphere with small fragments reaching the Earth at roughly 16:44 UTC on 2 June 2018 near the border of Botswana and South Africa. It had been discovered only 8 hours earlier by the Mount Lemmon Survey, Arizona and based on 1+1⁄2 hours of observations, was calculated to have a roughly 85% chance of impact likely somewhere between Australia and Madagascar.

References

  1. ↑ "Two craters that launched 1000 meteorites". New Scientist . May 11, 2012.
  2. ↑ S. J. Bus & R. P. Binzel (2002). "Phase II of the Small Main-belt Asteroid Spectroscopy Survey: A feature-based taxonomy". Icarus. 158 (1): 146. Bibcode:2002Icar..158..146B. doi:10.1006/icar.2002.6856. S2CID   4880578.
  3. ↑ R. P. Binzel & S. Xu (1993). "Chips off of asteroid 4 Vesta: Evidence for the parent body of basaltic achondrite meteorites". Science. 260 (5105): 186–91. Bibcode:1993Sci...260..186B. doi:10.1126/science.260.5105.186. PMID   17807177.
  4. ↑ V. Carruba; et al. (2005). "On the V-type asteroids outside the Vesta family". Astronomy & Astrophysics. 441 (2): 819–829. arXiv: astro-ph/0506656 . Bibcode:2005A&A...441..819C. doi:10.1051/0004-6361:20053355.
  5. ↑ Galiazzo, M. A.; Silber, E. A.; Bancelin, D.; et al. (2016). "V-type Near-Earth asteroids: dynamics, close encounters and impacts with terrestrial planets". Astronomische Nachrichten. 338 (4): 375–384. arXiv: 1610.04786 . Bibcode:2017AN....338..375G. doi:10.1002/asna.201613273.
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