R-type asteroids are moderately bright, relatively uncommon inner-belt asteroid

Asteroid

Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

s that are spectrally intermediate between the V

V-type asteroid

The spectra of the V-type asteroids or Vestoids are similar to that of 4 Vesta, by far the largest asteroid in this class ....

 and A-type asteroid

A-type asteroid

A-type asteroids are relatively uncommon inner-belt asteroids that have a strong, broad 1 µm olivine feature and a very reddish spectrum shortwards of 0.7 µm. They are thought to come from the completely differentiated mantle of an asteroid....

s. The spectrum shows distinct olivine

Olivine

The mineral olivine is a magnesium iron silicate with the formula 2SiO4. It is a common mineral in the Earth's subsurface but weathers quickly on the surface....

 and pyroxene

Pyroxene

The pyroxenes are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems...

 features at 1 and 2 micrometre

Micrometre

A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...

s, with a possibility of plagioclase

Plagioclase

Plagioclase is an important series of tectosilicate minerals within the feldspar family. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a solid solution series, more properly known as the plagioclase feldspar series...

. Shortwards of 0.7 μm the spectrum is very reddish.

The IRAS

IRAS

The Infrared Astronomical Satellite was the first-ever space-based observatory to perform a survey of the entire sky at infrared wavelengths....

 mission has classified 4 Vesta

4 Vesta

Vesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about . It was discovered by Heinrich Wilhelm Olbers on March 29, 1807, and is named after the Roman virgin goddess of home and hearth, Vesta....

, 148 Gallia

148 Gallia

148 Gallia is a large main-belt asteroid. It is classified as one of the few R-type asteroids.Gallia was discovered by the brothers Paul Henry and Prosper Henry on August 7, 1875, but the credit for this discovery was given to Prosper. It is named after the Latin name for Gaul .- References :...

, 246 Asporina

246 Asporina

246 Asporina is a sizeable Main belt asteroid. It is classified as one of the few R-type asteroids.It was discovered by A. Borrelly on March 6, 1885 in Marseilles and was named after Asporina, a goddess worshipped in Asia Minor.- References :...

, 349 Dembowska

349 Dembowska

Asteroid 349 Dembowska is named in honor of the Baron Hercules Dembowski, an Italian astronomer who made significant contributions to research on double and multiple stars. The asteroid was discovered over a century ago on December 9, 1892, by the French astronomer Auguste Charlois while working at...

, 571 Dulcinea

571 Dulcinea

- External links :*...

 and 937 Bethgea

937 Bethgea

937 Bethgea is an S or R-type asteroid belonging to the Flora family in the Main Belt. Its rotation period is 8.356 hours.-External links:*...

 as type R; however, the re-classification of Vesta, the V archetype, is debatable. Of these bodies, only 349 Dembowska

349 Dembowska

Asteroid 349 Dembowska is named in honor of the Baron Hercules Dembowski, an Italian astronomer who made significant contributions to research on double and multiple stars. The asteroid was discovered over a century ago on December 9, 1892, by the French astronomer Auguste Charlois while working at...

 is recognized as being type R when all wavelengths are taken into account.

See also

• Asteroid spectral types
  Asteroid spectral types
  Asteroids are assigned a type based on spectral shape, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition...