keskmise albeedoga metallilise koostisega asteroid, mis võib olla raudmeteoriitide ja enstatiit-kondriitide allikaks
medium albedo asteroid supposed to have a metallic composition and to be the progenitor both of differentiated iron-nickel meteorites and enstatite chondrites
M-type asteroids are a spectral class of asteroids which appear to contain higher concentrations of metal phases (e.g. iron-nickel) than other asteroid classes, and are widely thought to be the source of iron meteorites.