M-type asteroids are a spectral class of asteroids which appear to contain higher concentrations of metal phases than other asteroid classes, and are widely thought to be the source of iron meteorites.
Image of the M-type asteroid 21 Lutetia taken by the ESA Rosetta Spacecraft during a flyby in 2010
An iron–nickel meteorite with characteristic Widmanstätten pattern.
A mesosiderite showing a mixture of metals and silicates.
An enstatite chondrite displaying a mix of metals and silicates (enstatite).
An asteroid is a minor planet—an object that is neither a true planet nor a comet—that orbits within the inner Solar System. They are rocky, metallic, or icy bodies with no atmosphere. The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres, a dwarf planet almost 1000 km in diameter.
2013 EC, shown here in radar images, has a provisional designation
A composite image, to the same scale, of the asteroids imaged at high resolution prior to 2012. They are, from largest to smallest: 4 Vesta, 21 Lutetia, 253 Mathilde, 243 Ida and its moon Dactyl, 433 Eros, 951 Gaspra, 2867 Šteins, 25143 Itokawa.
Vesta (left), with Ceres (center) and the Moon (right) shown to scale
Phobos
