As part of the Pulkovo program for the study of near-Earth objects, more than 1500 observations of asteroid 2023 BU, which was discovered at the very beginning of 2023 just a few days before its extremely close approach to the Earth at a distance of about 3.5 × 106 m from its surface, were made at the MTM-500M telescope. It was one of the closest encounters of an asteroid with the Earth ever recorded, which caught the attention of astronomers around the world. Based on the observations of this asteroid, its orbit was refined and the orbital evolution was studied. In addition, estimates of the influence of solar radiation pressure and the Yarkovsky effect were made, which is relevant due to the problem of asteroid and comet hazard.

Asteroid 2022 AE1 with a diameter of about 70 m, discovered at the very beginning of 2022, approached the Earth on December 31, 2021 at a minimum distance of 0.0664 au. The potential hazard of a collision with the Earth during the next close approach in 2023 was estimated by astronomers at 1 in 1700, which raised widespread public concern. Subsequent observations made it possible to refine the asteroid's orbit and showed that the collision will be avoided. However, the upcoming close encounters of this asteroid with the Earth and, especially, with Venus, as well as possible approaches with the main belt asteroids, require not to weaken the attention to this object. Gravitational and non-gravitational effects can have a significant impact on its orbit and, as a consequence, lead to a collision with one of the inner planets. In this work, the displacements of asteroid 2022 AE1 under the influence of solar radiation pressure were calculated over several time intervals for various values of the average density of the object. Furthermore, the diurnal and seasonal components of the Yarkovsky effect were calculated for various rotation periods and axial tilt angles of the asteroid. As a result of the simulation, possible orbits of the asteroid were obtained and a probability estimation of the asteroid collision with the Earth was made.

Asteroids 2010 TK7 and 2020 XL5 are of particular interest because of their behavior, which is similar to the so-called trojan asteroids. In this paper, computer simulations of the orbital evolution of the asteroids in question were carried out using the EPOS software system. The results of the computer simulations suggest that the Earth trojans were not ordinary trojans in the recent past and will most likely shift to another type of orbit in the distant future.

Представлены результаты выявления астероидов, потенциально опасных для внутренних планет. Исследовано орбитальное движение астероида 2022 АЕ1, троянцев Земли (2010 TK7, 2020 XL5) и «рукотворного» астероида 2020 SO. The results of the detection of potentially hazardous asteroids for the inner planets are presented. The orbital motion of asteroid 2022 AE1, the Earth Trojans (2010 TK7, 2020 XL5), and the “man-made” asteroid 2020 SO has been studied.

The astrometric and photometric series of observations of potentially hazardous asteroid (276033) 2002 AJ129 were obtained with MTM-500M telescope of Pulkovo Observatory in the period of its close approach to the Earth on February 4, 2018. The orbital evolution was studied and the influence of non-gravitational effects (solar ra-diation pressure and the Yarkovsky effect) was estimated. The axial rotation period (P = 3.9222 +/- 0.0008 h) of the asteroid and the color indices (B-V = 0.687 +/- 0.050, V-R = 0.405 +/- 0.027, R-I = 0.178 +/- 0.044) were determined from the photometric series of observations.

In the frame of this study astrometric observations of an unusual object 2020 SO - a newly discovered asteroid that turned out to be a Centaur upper-stage booster from 1960s - during its two close approaches to the Earth in December, 2020 and February, 2021 were carried out using two telescopes of Pulkovo observatory. The orbit of the object in question was determined and its future orbital evolution was modelled.

The asteroid (13553) Masaakikoyama was observed with the ZA-320M and MTM-500M telescopes of the Pulkovo observatory in August and September 2018. Its axial rotation period was estimated based on the observed sections of the light curve (and additional observational data provided by B.D. Warner) at 97.2 ± 0.3 h. This estimation was made difficult by the fact that the period is commensurable with a day. The light curve has certain features suggestive of tumbling rotation and a complex shape. The orbit of (13553) Masaakikoyama was improved using the obtained astrometric positions of the asteroid.

Observations of potentially hazardous asteroid 2017 VR12 during its close approach to the Earth were made at Pulkovo Observatory via ZA-320M telescope at the end of February and the beginning of March 2018. Orbital elements of the asteroid were improved basing on the obtained astrometric data. The orbital evolution was studied and the influence of non-gravitational effects was estimated. The axial rotation period of the asteroid was determined from photometric data.

Astrometric and photometric observations of two near-Earth asteroids having poorly-defined axial rotation periods – Masaakikoyama (13553) and 5131 (1990 BG) – were performed using two telescopes of the Pulkovo Observatory (CAO RAS). Both asteroids in question have proved to be very slow rotators with signs of tumbling. Using the data obtained their periods were derived (97.1 ± 0.2 and 157.82 ± 0.2 hours, respectively), dense lightcurves were obtained. Accuracy of the orbital elements of the asteroids was also improved.

Astrometric and photometric observations of asteroids 276033 (2002 AJ129) and 2017 VR12 (both classified as a "Potentially Hazardous Asteroids" by the Minor Planet Center) were made using two telescopes of the Pulkovo Observatory (CAO RAS). The data was processed and the lightcurves of the objects were obtained. Accuracy of the orbital elements of the asteroids was estimated on the basis of the data obtained and the data from the Minor Planet Center.

Ground-based baseline observations of the potentially hazardous asteroid 2014 JO25 were made. The data were processed and the accuracy of the orbital elements of the asteroid was estimated on the basis of the obtained observations and the data from the Minor Planet Center. Also, the estimation of BVRI color indices of the asteroid was made.

In 2017, Pulkovo observatory organized two campaigns of baseline observations of two asteroids during their approaches to the Earth: 2014 JO25 (on April) and (418094) 2007 WV4 (on June). The goal of the campaigns was development of method of construction of precise asteroid orbits using short-time (1-2 hours) simultaneous observations from two observatories (triangulation method). Six observatories participated in the 2017 campaigns: Ussuriisk Astrophysics Observatory of RAS, Gissar and Sanglokh observatories of Institute of Astrophysics of Tajikistan, Zvenigorod Observatory of Institute of Astronomy of RAS, Pulkovo Observatory of RAS, Mountain Astronomical Station of Pulkovo Observatory. The orbit constructed with this method for 2014 JO25 asteroid is close to the orbit published on the MPC web-site that was constructed with more than 1.5 thousand observations of many observatories from 2011 to 2017. The results of the campaigns show that given existing accuracy of astrometric measurements, simultaneous observations of two observatories during more than 1 hour and the parallax angle of more than 10 arcmin are needed to construct sufficiently precise orbit. Also, the estimation of BVRI color indices of 2014 JO25 asteroid was made.

Using the telescopes ZA-320 M and MTM-500 M of Pulkovo Observatory (Russia), we have carried out astrometric and photometric observations of the asteroid (367943) Duende (2012 DA14) immediately after its close approach to the Earth occurred on 2013 February 15. We have obtained a series of its astrometric positions, colour indices and two fragments of its light curve. By numerically integrating, we have studied the evolution of the asteroid's orbit. Also, the influence of solar radiation pressure and Yarkovsky effect on the asteroid was estimated. The fitting of the asteroid rotation model to the observed light curve indicates that during its closest approach to the Earth, it had tumbling rotation regime.

The use of ground-based and space baseline observations of Solar System bodies is considered. Baseline observations allow one to determine the distance to observed objects and (in some cases) the parameters of their orbital motion. Certain results of baseline observations of near-Earth asteroids and the results of model analysis of spacecraft observations are presented.

Observational Astrometry Laboratory and Ephemeris Provision Sector of Pulkovo Observatory carry out a joint multipurpose research on asteroids belonging to various groups. Astrometric and photometric observations are done using ZA–320M and MTM–500M telescopes located at Pulkovo and in Northern Caucasus mountains, correspondingly. We obtain lightcurves that allow us to determine spin parameters and shapes of asteroids. Their color indices and taxonomy classes are derived from wideband filter observations. Improvement of asteroid orbits is achieved by doing positional measurements. Orbital evolution of asteroids is modelled, taking into account also non-gravity forces, including light pressure and Yarkovsky effect. NEAs, as well as binary asteroids, take an important place in our investigations. Quasi-satellites of Venus, Earth, and Mars are new targets of our research, one of the examples being 2012DA14 that approached Earth in early 2013; many MTM–500M observations of this asteroid were obtained around the date of approach.