A Survey and Analysis of Spitzer Infrared Spectrograph Spectra of T Tauri Stars in Taurus

摘要

We present mid-infrared spectra of T Tauri stars in the Taurus star-formingregion obtained with the Spitzer Infrared Spectrograph (IRS). For the firsttime, the 5-36 micron spectra of a large sample of T Tauri stars belonging tothe same star-forming region is studied, revealing details of the mid-infraredexcess due to dust in circumstellar disks. We analyze common features anddifferences in the mid-IR spectra based on disk structure, dust grainproperties, and the presence of companions. Our analysis encompasses spectralenergy distributions from the optical to the far-infrared, a morphologicalsequence based on the IRS spectra, and spectral indices in IRS wave bandsrepresentative of continuum emission. By comparing the observed spectra to agrid of accretion disk models, we infer some basic disk properties for oursample of T Tauri stars, and find additional evidence for dust settling.