Spectral Energy Distributions of Passive T Tauri Disks: Inclination

We compute spectral energy distributions (SEDs) for passive T Tauri disksviewed at arbitrary inclinations. Semi-analytic models of disks in radiativeand hydrostatic equilibrium are employed. Over viewing angles for which theflared disk does not occult the central star, the SED varies negligibly withinclination. For such aspects, the SED shortward of ~80 microns is particularlyinsensitive to orientation, since short wavelength disk emission is dominatedby superheated surface layers which are optically thin. The SED of a nearlyedge-on disk is that of a class I source. The outer disk occults inner diskregions, and emission shortward of ~30 microns is dramatically extinguished.Spectral features from dust grains may appear in absorption. However,millimeter wavelength fluxes decrease by at most a factor of 2 from face-on toedge-on orientations. We present illustrative applications of our SED models. The class I source04108+2803B is considered a T Tauri star hidden from view by an inclinedcircumstellar disk. Fits to its observed SED yield model-dependent values forthe disk mass of ~0.015 solar masses and a disk inclination of ~65 degreesrelative to face-on. The class II source GM Aur represents a T Tauri starunobscured by its circumstellar disk. Fitted parameters include a disk mass of\~0.050 solar masses and an inclination of ~60 degrees.Comment: Accepted to ApJ, 20 pages, 7 figures, aaspp4.st