Systematic variations in the wavelength dependence of interstellar linear polarization
D. C. B. Whittet, P. G. Martin, J. H. Hough, M. F. Rouse, J. A. Bailey, D. J. Axon;
ApJ, 1992, 386, 562
ABSTRACT:New observations of the wavelength dependence of interstellar linear polarization, p(lambda), which
were performed to investigate the influence of the environment on the
effective size distribution of the aligned polarizing particles, are
presented.
Optical and IR measurements were obtained simultaneously in eight
photometric passbands between U and K, giving a coherent data set for a total of 105
reddened stars.
The contention that variations of K and lambda-max are
correlated is confirmed, and the empirical linear relationship between K and
lambda-max found by Wilking et al.
(1980, 1982, 1983) is revised to K + 0.01 +/-0.05
+ (1.66 +/-0.09)lambda-max.
There is some cosmic scatter of the data
about this line.
The same linear dependence of K on l-max seen overall
provides a consistent representation of the systematic polarization in
changes within individual regions with rather differing environments.
It is
argued that the grain size distribution in dense regions is modified by
coagulation which removes the smaller particles without major modification of the
larger ones.
KEYWORDS: cosmic dust, interstellar matter, linear polarization, wavelengths, astronomical photometry, astronomical polarimetry, infrared photometry
PERSOKEY:polarisation, optical, nir. extinction, dust, ,
CODE: whittet92