R-type asteroids are moderately bright, relatively uncommon inner-belt asteroids that are spectrally intermediate between the V and A-type asteroids. The spectrum shows distinct olivine and pyroxene features at 1 and 2 micrometres, with a possibility of plagioclase. Shortwards of 0.7 μm the spectrum is very reddish.

The IRAS mission has classified 4 Vesta, 246 Asporina, 349 Dembowska, 571 Dulcinea and 937 Bethgea as type R; however, the re-classification of Vesta, the V archetype, is debatable. Of these bodies, only 349 Dembowska is recognized as being type R when all wavelengths are taken into account.


As of February 2019, at least 5 asteroids have been classified as R-type:[1]

Designation Class Diam. Refs
349 Dembowska main-belt 139.77 km MPC · JPL
1904 Massevitch main-belt 13.503 km MPC · JPL
2371 Dimitrov main-belt 7.465 km MPC · JPL
5111 Jacliff main-belt 6.447 km MPC · JPL
(257838) 2000 JQ66 Amor 0.78 km MPC · JPL
Diameter: averaged estimates only; may change over time


  1. ^ "JPL Small-Body Database Search Engine: spec. type = R (SMASSII)". JPL Solar System Dynamics. Retrieved 2019-03-17.

See also