ИСТИНА

Since 2019, polarimetric monitoring of near-Earth asteroids (NEAs) has been conducted at the 2.6-m telescope at the Crimean Astrophysical Observatory (CrAO) and the 2-m telescope at the Peak Terskol Observatory (PTO, a branch of INASAN). Polarimetric studies, especially over a wide range of phase angles, are essential for determining polarization phase dependences (PhDP) for different taxonomic classes, as well as estimating albedo and size.To date, polarimetric properties of more than 30 near-Earth asteroids have been measured. This represents a significant contribution to the total number (approximately 26) of observed NEAs published to date. In the period from July 23 to August 3, 2025, observations of the low-albedo NEA 2100 Ra-Shalom were carried out in the phase angle range of 84–73° using the CrAO and PTO polarimeters in the V and R bands. For comparison, the data of different authors are presented for other low-albedo asteroids 101955 (Bennu), 152679 (1998 Ku2), 162173 (Ruygu), 3200 Phaethon. Additionally, data from NEAs 25330 and 417264 obtained using our program are shown. The figure shows that the PhDP of Ra-Shalom differs significantly from the data for Phaethon and four asteroids 101955, 152679, 162173, 25330. The latter form a group with close polarization curves. However, the PhDP of Ra-Shalom coincides well with the polarization of NEA 417264. In general, it is obvious that low-albedo asteroids demonstrate significant scattering of the degree of polarization on the plot Pr vs phase angle. Possible reasons will be discussed.