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Session 41 - T Tauri Stars & Protostellar Regions.
Display session, Wednesday, June 11
South Main Hall,
If we are to test current models of star formation, we need to understand the physical structure of the envelopes around young stellar objects. Different star formation models make different predictions about the density distribution expected around a young star. However, such density distributions are difficult to probe around low mass stars. One technique that has been used very successfully is far-infrared mapping. Dust continuum emission, if measured at high spatial resolution, can be used to test star formation models. By combining the expected density distribution with a radiative transfer code, it is possible to predict what the expected far-infrared distribution would look like. Through an exploration of parameter space (including density gradient, size and optical depth of any expected disks, dust properties, etc), the range of physical parameters consistent with the observations can be assessed.
This technique has been used on several individual low mass stars (such as L1551 IRS 5), and a number of higher mass objects (including Herbig Ae/Be stars and more massive embedded sources) quite successfully. However, a systematic study with this technique of low mass stars has not been presented previously. We used the Yerkes FIR Camera and the Kuiper Airborne Observatory to map the far-infrared emission for several sources in the Taurus molecular cloud complex, including both embedded stars and T Tauri stars. These stars are part of a broad based continuum/molecular line observational program to assess star formation processes for low mass stars.
Using the Yerkes FIR Camera, we obtained 100 and 200 \mum diffraction limited maps for 10 low mass stars in Taurus and similar low mass star forming regions. For a few of the stars, we also obtained 60 \mum observations. At the distance of Taurus, the 100 \mum size scale corresponds to a linear scale of 0.02pc. We present the initial results of our far-infrared mapping program for these young stellar objects and discuss the implications for current models of low mass star formation.
Program listing for Wednesday