Discs and the 10- m silicate spectra of young stellar objects with non-photospheric continua

• DOI: 10.1046/j.1365-8711.2001.03955.x
• Publication Date: 2003-03-12T13:26:22Z
• Authors: J. E. Bowey; A. J. Adamson
• Keywords: 0103 physical sciences; 01 natural sciences

ABSTRA C T Dust emission in the non-photospheric 10-mm continua of HL Tau and Taurus-Elias 7 (Haro6-10, GV Tau) is distinguished from foreground silicate absorption using a simple disc model with radial power-law temperature and mass‐density distributions based on the IR‐ submm model of T Tauri stars by Adams, Lada & Shu with foreground extinction. The resulting 10-mm absorption profiles are remarkably similar to those of the field star TaurusElias 16 obtained by Bowey, Adamson & Whittet. The fitted temperature indices are 0.44 (HL Tau) and 0.33 (Elias 7) in agreement with Boss’s theoretical models of the 200‐300 K region, but lower than those of IR‐submm discs (0.5‐0.61; Mannings & Emerson); a significant fraction of the modelled 10-mm emission of HL Tau is optically thin, whilst that of Elias 7 is optically thick. We suggest that HL Tau’s optically thin component arises from silicate dust within low-density layers above an optically thick disc.