Grain Alignment and Polarization in Molecular Clouds
Event date
Le Ngoc Tram
Event Type

For information on how to participate in the teletalks, please check the SOFIA Tele-Talk page.

Observations of polarized thermal dust emission toward molecular clouds hosted by an intense radiation source (i.e., massive stars) usually report a trend in which the fractional polarization p(%) first increases and decreases as the grain temperature Td increases. The latter trend differs from the prediction of the popular RAdiative Torques (RATs) alignment theory, which implies a monotonic increase of p(%) with Td. Moreover, polarimetric observations toward starless cores and protostars show the decrease of the p(%) with the visual extinction AV, which is known as “polarization hole”. We performed theoretical calculations of the degree of dust polarization by simultaneously considering the dust grain alignment and rotational disruption by RATs. Our theoretical prediction could successfully explain the observational p(%)-Td correlation in molecular clouds and the polarization hole toward starless cores and protostars.

Speaker Materials
Audio file