A MILLIMETER-WAVE INTERFEROMETRIC STUDY OF DUST AND CO DISKS AROUND LATE SPECTRAL TYPE STARS IN TAURUS-AURIGA

We present a new millimeter survey of 23 pre-main-sequence stars in the Taurus-Auriga star-forming region. The main goal of the project was to identify circumstellar disks around stars of late spectral types (M-* less than or similar to 0.7 M-circle dot). We used the IRAM Plateau de Bure Interferometer to obtain observations at 1.3 mm, 2.7 mm, and the CO J = 1-0 and J = 2-1 lines. We detected eight sources in continuum emission, with new detections of CIDA-1 and CIDA-8 at 1.3 mm. Overall, we find that circumstellar disks around stars with spectral types later than M2 tend to have smaller millimeter continuum fluxes than those around earlier type stars. We also present four detections of disks in their CO line emission (LkH alpha 358, GO Tau, Haro 6-13, IRAS 04385+2550). By mapping the rotation of the resolved CO emission from the circumstellar disks, we obtain estimates of the dynamical mass of the central stars.