Spectrophotometry at 10 microns at T Tauri stars

We present new 8--13 μm spectra of 32 T Tau, or related young, stars. Silicate emission features are commonly seen. Absorptions occur less frequently but also match the properties of silicate materials. The shape of the emission feature suggests that a more crystalline grain is responsible in the T Tau stars than those of the Trapezium region. We investigate the evolution of the silicate component of the circumstellar shell around T Tau stars and its dependence upon stellar wind activity, visual linear polarization, and extinction. Several correlations suggest that the shells are likely to be flattened, disklike structures rather than spherical