ISSN 0884-5913, Kinematics and Physics of Celestial Bodies, 2015, Vol. 31, No. 6, pp. 281–285. © Allerton Press, Inc., 2015. Original Russian Text © S.V. Zaitsev, N.N. Kiselev, V.K. Rosenbush, S.V. Kolesnikov, 2015, published in Kinematika i Fizika Nebesnykh Tel, 2015, Vol. 31, No. 6, pp. 23–31. 281 INTRODUCTION The phase dependence of linear polarization of light scattered by the surfaces of atmosphereless bodies of the Solar System (asteroids and satellites of principal planets) is a main source of information on the albedo, composition, and physical and optical properties of their surfaces. To study the polarization char- acteristics of high-albedo atmosphereless bodies is of particular interest, since, when approaching oppo- sition, they demonstrate the nonlinear increase of the surface brightness called the photometric (bright- ness) opposition effect (BOE), the regular branch of negative polarization, and the narrow secondary minimum of negative linear polarization called the polarimetric opposition effect (POE) [12, 15]. The main mechanisms explaining the above-mentioned effects in the intensity and polarization are the coherent strengthening of the backscattering (the effect of weak localization of photons), the near- field effects, and the scattering on individual particles [15, 17, 18, 24, 28]. Relative contributions of these mechanisms are determined by the physical properties of the surfaces, such as the albedo, packing density of particles, sizes of monomers composing the aggregate particles, shapes, etc. Because of this, to study the phase dependences of polarization of light scattered by the surfaces of atmosphereless bod- ies at small and large phase angles and to determine the shape and amplitude of the polarimetric oppo- sition effect may contribute to the development of the light scattering models for regolith surfaces and to the evaluation of the physical characteristics of celestial bodies. Though the exact profiles of polari- metric opposition effect of high-albedo atmosphereless bodies of the Solar System have not been com- pletely determined yet, it is clear that they differ for different mechanisms forming the polarization and for different surface properties. One of the high-albedo atmosphereless bodies of the Solar System that demonstrates the photometric opposition effect is Rhea, the second largest moon of Saturn. Its diameter is 764 km [27], density is 1.23 g/cm 3 [11], and geometric albedo is 0.81 at the wavelength λ = 510 nm [19]. The first photometric observations of Rhea were carried out in the 1960s [4, 9]. From these observations, it was found that the trailing hemisphere of the satellite is brighter than the leading one. From the results of spectral observa- tions, Fink et al. [8] and Clark et al. [6] found that the surface of Rhea is covered with water ice. The sub- sequent spectral observations confirmed this conclusion and allowed the surface composition to be deter- mined more precisely. The first images of the satellite’s surface obtained with the Voyager spacecraft [25] showed that the surface of the trailing hemisphere of Rhea is geologically younger as compared to the sur- face of the leading hemisphere. From the data acquired with the Cassini spacecraft, the variations of the spectral properties of Rhea over the surface were analyzed, the high-resolution maps [20, 26], the orbital curve, and the phase dependence of brightness of the satellite were built, and the photometric opposition effect was studied in a wide wavelength range [5, 13, 19]. Polarimetry of Saturn’s Satellite Rhea S. V. Zaitsev a , N. N. Kiselev a , V. K. Rosenbush a , and S. V. Kolesnikov b a Main Astronomical Observatory, National Academy of Sciences of Ukraine, ul. Akademika Zabolotnoho 27, Kyiv, 03680 Ukraine b Astronomical Observatory, Mechnikov University, ul. Marazlievskaya 1v, Odessa, 65014 Ukraine e-mail: sergio908@rambler.ru Received October 14, 2014 Abstract—Results of polarimetric observations of Saturn’s satellite Rhea obtained in the range of phase angles from 0.76° to 5.96° are presented. The observations were carried out in the WR spectral band (550–750 nm) at the 2.6-m telescope equipped with a single-channel photometer–polarimeter at the Crimean Astrophysical Observatory in the period from March 23, 2012, to May 2, 2014. From the results of the observations, the phase dependence of linear polarization of Rhea was built. The parameters of this dependence are compared to those of the high-albedo satellites of Jupiter, Japetus, and medium-albedo satellites of Uranus. The obtained results are discussed in terms of the currently available models of the light scattering by regolith surfaces. DOI: 10.3103/S0884591315060070 DYNAMICS AND PHYSICS OF BODIES OF THE SOLAR SYSTEM