Understanding the Diversity of Properties of Protoplanetary Disks in Tauru
First Author:
Nathan Crockett
Email: ncrocket AT umich.edu
University of Michigan
Ann Arbor, MI 48104 USA
Abstract
In a comprehensive study of all the stars surrounded by disks in the Taurus molecular cloud, Furlan et al. (2006) classified Spitzer IRS observations according the slope of the spectral energy distribution and the strength of the silicate emission feature. These observations characterize the dust settling and thus the depletion of dust in the upper layers of circumstellar disks. We combine these observations with submillimeter continuum observations from Andrews and Williams (2005), which probe the midplane in the outer regions of dust disks. Considering these data sets simultaneously, in effect, links the upper layers to the disk midplane. In particular, we are able to link the amount of dust settling in the upper layers to grain growth in the midplane, both quantified using our irradiated accretion disk models. Preliminary results indicate that disks with moderate grain growth in the midplane, signified by relatively steep submillimeter slopes, show a large range of dust depletion in the upper layers (from approximately 10-0.1% of the standard dust to gas mass ratio). In contrast, those disks with the flattest slopes in the millimeter are found to have the highest degrees of dust settling in the upper layers, suggesting that those disks are clearly in a much more advanced stage of evolution.
