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Paper: |
Near-Infrared Imaging Polarimetry of Bipolar Proto-planetary Nebulae |
Volume: |
449, Astronomical Polarimetry 2008: Science from Small to Large Telescopes |
Page: |
327 |
Authors: |
Murakawa, K.; Driebe, T.; Hofmann, K.; Meixner, M.; Ohnaka, K.; Oya, S.; Schertl, D.; Weigelt, G.; Ueta, T. |
Abstract: |
We present results of radiative transfer modeling of two bipolar
proto-planetary nebulae based on the data archives of HST/NICMOS
imaging polarimetry. We constrained the model parameters by fitting the
spectral energy distributions, the intensity and polarization images,
and assumed multiple grain models in different geometry space. From our
sample, we found that (1) model geometries with a disk reproduce the
bipolar appearance with a narrow waist, (2) grains in the bipolar lobes
have submicron sizes, but ∼10μm or larger sizes are expected
in the equatorial region, and (3) the grain sizes in the disk correlate
to the disk geometry, but not the stellar temperature, luminosity, or
lobe shape. Our results agree with the disk/reservoir hypothesis in PN
shaping. |
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