Vesta is technically a minor-planet roughly 500 kilometers in diameter, with lots of other smaller "V type" asteroids with a similar spectral signature roaming around throughout its local area. What the data linking IIIAB irons to HED achondrites seems to tell us, is that a Vestan-like differentiated parent body, but not Vesta itself (as it is still intact), was completely obliterated in order to give us both IIIAB irons and HED achondrites from the same parent body.
Keeping it simple, differentiation, also known as 'planetary differentiation' is the process of an asteroid getting so big that most of the metal distributed throughout its mass is pulled by gravity down to the center to form a 'core'. This leaves the lighter rocky material to float above the iron-nickel core and form a 'mantle'. This little bit of information is a keyhole that will allow those new to meteorites to glimpse just how intertwined planetary science and meteorites truly are.
