  In this work we study the link between the evolution of the internal
structure of Vesta and thermal heating due to 26Al and 60Fe and long-lived
radionuclides, taking into account the chemical differentiation of the body and
the affinity of 26Al with silicates. Differentiation takes place in all
scenarios in which Vesta completes its accretion in less than 1.4 Ma after the
injection of 26Al into the Solar Nebula. In all those scenarios where Vesta
completes its formation in less than 1 Ma from the injection of 26Al, the
degree of silicate melting reaches 100 vol. % throughout the whole asteroid. If
Vesta completed its formation between 1 and 1.4 Ma after 26Al injection, the
degree of silicate melting exceeds 50 vol. % over the whole asteroid but
reaches 100 vol. % only in the hottest, outermost part of the mantle in all
scenarios where the porosity is lower than 5 vol. %. If the formation of Vesta
occurred later than 1.5 Ma after the injection of 26Al, the degree of silicate
melting is always lower than 50 vol. % and is limited only to a small region of
the asteroid. The radiation at the surface dominates the evolution of the crust
which ranges in thickness from 8 to about 30 km after 5 Ma: a layer about 3-20
km thick is composed of primitive unmelted chondritic material while a layer of
about 5-10 km is eucritic.
