A

David

Darling

subdwarf

A subdwarf is a star that is smaller and less luminous by one to two magnitudes (2.5–6 times fainter) than a normal dwarf (main sequence) star of the same spectral type. Subdwarfs are mainly old, galactic halo population II objects of types F, G, and K. They are denoted by the prefix "sd", as in sdK7, and are placed in luminosity class VI.