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N. J. Evans II (Univ. of Texas at Austin), J. M. C. Rawlings (Univ. College London), Y. L. Shirley (Univ. of Texas at Austin), L. G. Mundy (Univ. of Maryland)
We have modeled the emission from dust in pre-protostellar cores, including a self-consistent calculation of the temperature distribution for each input density distribution. We have modeled the cores with Bonnor-Ebert spheres and power law density distributions. The Bonnor-Ebert spheres fit the data well for all three cores we have modeled. The dust temperatures decline to very low values (Td ~7.5 K) in the centers of these cores, strongly affecting the dust emission. Compared to earlier models that assume constant dust temperatures, we find higher central densities and smaller regions of relatively constant density. Indeed, for L1544, a power law density distribution like that of a singular, isothermal sphere cannot be ruled out. For the three sources we have modeled, there seems to be a sequence of increasing central condensation, from L1512 to L1689B to L1544. The denser two have spectroscopic evidence for contraction, suggesting an evolutionary sequence. This research was supported by NASA, the Fulbright program, PPARC, NWO, and NOVA.