| Polarimeric observations of the asteroids 1 Ceres and 4 Vesta
were carried out at the 70-cm telescope of Astronomical Observatory
of Kharkiv National University from December 1998 to May 1999 and in
September 2002. Polarimetric data were taken in VR standard spectral
bands with a single-channel photometer-polarimeter, that worked on the
modulation principle with a rapidly rotating polaroid. For the asteroid
4 Vesta observations were made in the range of phase angle from 2.5 to
25.3deg and was obtained phase dependence of the polarization that consists
of negative and positive branches. The characteristics of the phase
dependence Pmin=-0.67%, ALPHAmin=7.7deg, ALPHAinv=22.6deg and h=0.05 have been obtained. Geometric albedo of the asteroid has been calculated and equal to Pv(h)=0.35, Pv(Pmin)=0.2.
For the asteroid 1 Ceres observations were made in the range of phase angle
from 11.6 to 21.7deg. The obtained polarization data and Asteroid Polarimetry
Database (http://pdssbu.astron.umd.edu/SBNapd/archive/APD/opd.tab) have made
it possible to composite the phase dependence of linear polarization of the
asteroid in R-band. Parameters of the phase dependence are Pmin=-1.52%,
ALPHAmin=7.8deg, ALPHAinv=17.7deg and h=0.263.
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