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| Paper: |
Does Purcell Alignment Work, After All?: Multi-Band Polarimetry
of Stars Behind IC 63 |
| Volume: |
449, Astronomical Polarimetry 2008: Science from Small to Large Telescopes |
| Page: |
154 |
| Authors: |
Andersson, B.; Piirola, V. |
| Abstract: |
Grain alignment was for a long time thought to be driven by grain
spin-up caused by the ejection of newly formed H2 molecules from
their surfaces. Modern theory has downplayed the likely contribution
from such “Purcell Alignment", instead favoring direct radiative torques
on the grains (Lazarian & Hoang 2007, and references therein), while
leaving the possibility open for a role for Purcell-like (“pin-wheel")
alignment in some special circumstances (Draine & Weingartner 1997;
Hoang & Lazarian 2008). To observationally address the contribution of
such pin-wheel alignment, we are studying the wavelength dependent
polarization induced by dust in the reflection nebula IC 63.We find a
tantalizing indication of active pin-wheel alignment. One sight line,
probing an area of NIR fluorescent emission, shows both a higher level
of polarization and a smaller wavelength of maximum polarization – both
tracers of enhanced grain alignment – than other sight lines through the
nebula. |
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