On the possible identification of ‘solid-state’ lines in T-Tauri stars

The possibility is considered that irradiated amethystlike grains are responsible for some of the unidentified absorption lines in the spectrum of the YY Orionis star S CrA. The unidentified absorption lines in the star's spectrum are at 4305, 4310, 4681, 4764, and 4782 A, as well as near 3630 A; the stable absorption features of amethyst in the region of interest are at 3590, 4300, and 4700 A. A qualitative theoretical analysis is performed to determine whether the impurity concentration in the star's envelope is sufficient to produce the observed features. The results obtained support the possibility that irradiated amethystlike grains are one of the major mass constituents in the envelope of S CrA.