Interstellar extinction and polarization in the infrared
P. G. Martin, D. C. B. Whittet;
ApJ, 1990, 357, 113
ABSTRACT:The wavelength dependences of interstellar continuum extinction and polarization in the range 0.35-5 microns are examined.
The
existence of a universal extinction curve with power law index of about 1.8
extending from the near-IR to at least 5 microns appears to be established for both
diffuse and dense cloud dust.
The polarization yields evidence for some
degree of universality in the 1.6-5 micron regime which may be represented by a
power law with index 1.5-2.0, encompassing that for extinction.
The form of
the polarization curve in the IR seems independent of the wavelength at
which the degree of polarization peaks in the optical, implying that
variations in that wavelength are caused by changes in the optical properties of
the particle at blue-visible rather than IR wavelengths.
It is argued
that the more significant alterations of the grain size distribution from
one environment to another occur for the smaller particles.
KEYWORDS: cosmic dust, interstellar extinction, interstellar matter, molecular clouds, near infrared radiation, energy distribution, particle size distribution, stellar mass
PERSOKEY:polarisation, nir, extinction, ,
CODE: martin90