The crystalline fraction of interstellar silicates in starburst galaxies
  We present a model using the evolution of the stellar population in a
starburst galaxy to predict the crystallinity of the silicates in the
interstellar medium of this galaxy. We take into account dust production in
stellar ejecta, and amorphisation and destruction in the interstellar medium
and find that a detectable amount of crystalline silicates may be formed,
particularly at high star formation rates, and in case supernovae are efficient
dust producers. We discuss the effect of dust destruction and amorphisation by
supernovae, and the effect of a low dust-production efficiency by supernovae,
and find that when taking this into account, crystallinity in the interstellar
medium becomes hard to detect. Levels of 6.5-13% crystallinity in the
interstellar medium of starburst galaxies have been observed and thus we
conclude that not all these crystalline silicates can be of stellar origin, and
an additional source of crystalline silicates associated with the Active
Galactic Nucleus must be present.
