1.3 mm polarized emission in the circumstellar disk of a massive protostar
M. Fernández-López ... [et al.].
Serie: Trabajos publicados del IAR ; no. 1384
Resumen: 953We present the first resolved observations of the 1.3 mm polarized emission from the disk-like structure surrounding the high-mass protostar Cepheus A HW2. These CARMA data partially resolve the dust polarization, suggesting a uniform morphology of polarization vectors with an average position angle of 57[elevado a la]\circ +/- 6[elevado a la]\circ and an average polarization fraction of 2.0 % +/- 0.4 % . The distribution of the polarization vectors can be attributed to (1) the direct emission of magnetically aligned grains of dust by a uniform magnetic field, or (2) the pattern produced by the scattering of an inclined disk. We show that both models can explain the observations, and perhaps a combination of the two mechanisms produces the polarized emission. A third model including a toroidal magnetic field does not match the observations. Assuming scattering is the polarization mechanism, these observations suggest that during the first few 104 years of high-mass star formation, grain sizes can grow from 1 mu {{m}} to several 10s mum