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:
|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|
- "JPL Small-Body Database Search Engine: spec. type = R (SMASSII)". JPL Solar System Dynamics. Retrieved 2019-03-17. CS1 maint: discouraged parameter (link)