Author 1: Kiselev N. N. (Crimean Astrophysical Observatory, Institute of Astronomy of the RAS), Shcherbina M.P. (INASAN), Karpov N.V. (INASAN), Shein A.V. (INASAN), Sokolov I.V. (INASAN)

Title: Results of the “Polarimetric” Year 2024: Selected Outcomes of Polarimetric Observations of Planetary Satellites,  Main-Belt Asteroids, Near-Earth Objects, and the Transit of WASP-33b  at the 2-meter Telescope of the Terskol Observatory

Abstracts:  The longitude (orbital) dependence of the polarization of Jupiter’s satellite Io was measured. It was shown that the amplitude is approximately half an order of magnitude smaller compared to the amplitude measured by Zellner & Gradie in 1975. We conclude that the significant change in the longitudinal polarization dependence over nearly 50 years may be due to changes in the reflective properties of local surface areas on Io, caused by long-term variations in its local or global volcanic activity.

For the first time, the precise shape of the negative polarization branch of the E-type Main-Belt asteroid (44) Nysa was obtained. This enables computer modeling using the coherent backscattering method to determine the properties of particles on the rough (regolith) surface.

Data on the phase dependence of polarization for 12 Near-Earth Objects were obtained, with such data being recorded for the first time for some of them. The results will be discussed.

Polarimetric monitoring of the transit of WASP-33b—an exoplanet classified as a hot Jupiter—was conducted. The results will be discussed.

Author 2: Bakanas E. S. (Institute of Astronomy of the RAS),Barabanov S.I. (INASAN)

Title: Photometry of Selected Near-Earth Objects Using the Tycho Program

Abstracts:

Determining the physical characteristics of near-Earth asteroids, such as their taxonomic class, rotation period, and other parameters, is crucial, including for developing methods to mitigate potential threats to Earth posed by such objects.

Absolute photometry is one of the methods used to determine these physical characteristics. However, in real-world conditions, where photometric nights are almost entirely absent during observations, conducting absolute photometry becomes challenging. This is because, in addition to imaging the asteroid itself, images of standard stars—located at some distance from the target object—are required. The necessity of photometric nights is often unattainable. In such cases, differential photometry is performed, and the required data can be obtained from images of the target object using stars within the same frame.

Using photometric parameters of stars from the ATLAS catalog and the Tycho software package for image processing (https://www.tycho-tracker.com/) enables obtaining data in some cases without requiring standard star imaging outside the target object’s field. The report presents examples of using the Tycho Tracker program to assess taxonomic classification for several objects, including several near-Earth asteroids observed at the Terskol Observatory of INASAN during 2023–2024, and for comet R/2012 NJ La Sagra (based on archival data from Simeiz observations).