1 research outputs found
Polarization of stars with debris disks: comparing observations with models
The Space telescope carried out an unprecedented survey of nearby
stars for debris disks. The dust present in these debris disks scatters and
polarizes stellar light in the visible part of the spectrum. We explore what
can be learned with aperture polarimetry and detailed radiative transfer
modelling about stellar systems with debris disks. We present a polarimetric
survey, with measurements from the literature, of candidate stars observed by
DEBRIS and DUNES surveys. We perform a statistical analysis of the
polarimetric data with the detection of far-infrared excess by and
with a sample of 223 stars. Monte Carlo simulations were performed to
determine the effects of various model parameters on the polarization level and
find the mass required for detection with current instruments. Eighteen stars
were detected with a polarization per cent and
, but only two of them have a debris disk. No statistically
significant difference is found between the different groups of stars, with,
without, and unknown status for far-infrared excess, and presence of
polarization. The simulations show that the integrated polarization is rather
small, usually per cent for typical masses detected by their
far-infrared excess for hot and most warm disks. Masses observed in cold disks
can produce polarization levels above per cent since there is usually
more dust in them than in closer disks. We list five factors which can explain
the observed low-polarization detection rate. Observations with high-precision
polarimeters should lead to additional constraints on models of unresolved
debris disks.Comment: Corrected some quotations and typos and deleted superfluous
references. 20 pages, 5 figure