Astronomy Reports最新文献

Using a high-precision algorithm for interpreting transit light curves in a model of a classical eclipsing binary star-exoplanet system, we studied the possibility of determining the system parameters in the absence of a priori knowledge of the orbital eccentricity. It was shown that it is impossible to determine the exact value of the eccentricity and periastron longitude based on the main minimum of the transit light curve alone. Also, at an observational accuracy of ~1% of the eclipse depth, the uncertainty in the eccentricity and periastron longitude together causes a significant uncertainty in the values of the component radii (a two-threefold error relative to the true values) and the orbital inclination angle. However, the ratios of the system component radii and the limb darkening coefficients are determined with good accuracy. At an increase in the observational accuracy to 0.1% of the eclipse depth, it becomes possible to determine the component radii and the orbital inclination angle when interpreting the light curve with allowance for the eccentricity.

For the Tashanta point, 49°43(' )4('' ) N, 89°11(' )31('' ) E, Gorny Altai, data from continuous measurements of astroclimatic parameters of the surface layer, monthly average values of the total cloud cover, suspended water vapor from the Era5 atmospheric reanalysis database, and primary measurements of the altitude distribution of turbulence are presented. The results show unique astroclimatic and operational conditions, which probably make it one of the best places in the Russian Federation for submillimeter and optical range observatories.

The frame work of this study is the bi-elliptic restricted four body problem, where the largest primary ({{m}_{1}}) is assumed to be a radiating body and the other two massive bodies ({{m}_{2}}) and ({{m}_{3}}) are assumed to be oblate spheroids. The problem is restricted in the sense that the fourth body is assumed to be of infinitesimal mass. The goal of the paper is to study the so-called equilibrium points by generalizing R3BP to a non-coherent but highly practical R4BP model. The location of the planar equilibrium points according to this model is numerically studied for Sun–Earth–Moon system. The position of the triangular equilibrium points are also obtained analytically and graphically compared with numerically obtained values. Both the graphical and analytical studies confirms the high dependence of the position of the triangular equilibrium points on radiation pressure, however the collinear points were found to be less affected. The collinear points were found to be more affected by the oblateness of the second primary. The triangular equilibrium points were found to be stable for the third and fourth order resonance cases when the mass ratio is less than equal to a critical mass ratio. This critical mass ratio is also found to be dependent on the radiation pressure and phase angle ({{theta }_{0}}). The transition curve in the ((mu - {{epsilon }_{2}})) plane is plotted to find the value of ({{epsilon }_{2}}) for which the motion near triangular equilibrium points become unstable.

The results of the analysis of observational data of interplanetary scintillations obtained at the Big Synphasic Antenna radio telescope of the Lebedev Physical Institute (BSA LPI) before, during and after the magnetic storm that occurred on December 1–2, 2023. Observational data were compared with model calculations for corotating and propagating large-scale disturbances. The results of observations of scintillations of radio sources indicate that the magnetic storm that took place was caused by the superposition of two types of large-scale disturbances of the solar wind. On the day before the start of the magnetic storm, signs of interaction of the Earth’s magnetosphere with the corotating region of multi-velocity solar wind flows were observed, whereas later signs of disturbance of the magnetosphere by a coronal mass ejection propagating after the M9.8 flare on November 28, 2023 were observed.

Positional and multicolor photometric observations of near-Earth asteroids were carried out using the SBG telescope of the Kourovka Astronomical Observatory of Ural Federal University and the Zeiss-1000 telescope of the Simeiz Observatory of INASAN in 2022–2023. Based on the results of positional observations with the SBG telescope, improved orbital elements were obtained for seven asteroids. The periods of axial rotation of seven asteroids were estimated from photometric observations. Based on the results of photometric observations in the B, V, R, I filters, color indices were obtained for six asteroids.

The analysis of parameters of radio pulsars with periods (P > 5) s has been carried out. It was found that there is no clear dependence of (dP{text{/}}dt) on (P) on the ({ dP{text{/}}dt,P} ) diagram. The lack of dependence can be explained within the disk model. It is shown that the pulse width decreases with increasing period for the sample considered. It is the opposite of the dependence in the generally accepted pulsar model. It indicates that the distance from the surface of the neutron star to the radio emission generation region in the studied population depends on the period or that the magnetic field in the generation region has a non-dipolar structure. The possibility of explaining the longest intervals between successive pulses in pulsars J0901–4046 and J0250+5854 by the influence of drift waves at the periphery of the magnetosphere has been considered. Within the framework of the drift model, the calculated rotation periods in these pulsars turn out to be several times shorter than the observed intervals between successive pulses.

The rotation of the Milky Way halo in the solar vicinity is studied using kinematic data of the GAIA DR3 catalog for RR Lyrae variable stars with parallax errors of less than 20%. Two criteria were used for selecting halo stars: kinematic and spatial. In both approaches, we confirm the existence of weak rotation of the halo in the direction opposite to the rotation of the Galactic disk with velocities of (4.08 pm 2.19) km/s for the kinematic criterion and (9.49 pm 2.59) km/s for the spatial criterion.

The problem of equilibrium figures of two liquid masses in a state of tidal mutual capture is posed and solved. The condition of complete synchronous (orbital plus spin) rotation is satisfied in the system, and both bodies have the same masses and congruent ellipsoidal surfaces. For each figure, besides its own gravity and centrifugal forces, the attraction from the second body is taken into account in the tidal approximation. The spatial form of equilibrium figures as triaxial ellipsoids is found by an analytical and numerical method. The spin rotation of ellipsoidal equilibrium figures is established to occur not around small axes, as is usually assumed, but around the middle axes of the ellipsoids. This method is used to study the binary asteroid (190166) 2005 UP156, which approximately satisfies the initial conditions of the problem. The study showed that with the parameters known today, the system of two asteroids (190166) 2005 UP156 is nonequilibrium.

This manuscript illustrates the existence, locations, and stability of equilibrium points under the effect of Stokes drag in the restricted four-body problem (R4BP) with variable mass when all the primaries are source of radiation. The motion of the fourth body of negligible mass (infinitesimal mass) is effected by the motion of the primaries, and its motion is perturbed by the radiation pressure and Stokes drag. All the primaries are established at the vertices of an equilateral triangle and known as Lagrangian configuration. The dynamics of an infinitesimal body has been studied under the influences of radiation pressure of all the primaries with Stokes drag and variable mass. Jeans’ law and space time transformations of Meshcherskii have been used to formulate the equations of motion of the infinitesimal body. We have numerically investigated the existence and locations of the equilibrium points in the theoretical ranges of the parameters. The numerical investigations delved that all the equilibrium points are non-collinear, the collinear equilibrium points do not exist due to the presence of Stokes drag. Further, we have observed that all the equilibrium points are unstable for all values of the parameters considered. Moreover, the regions of motion have been drawn for different values of the parameters, i.e., for the radiation parameters ({{q}_{i}} (0 < {{q}_{i}} < 1),) (i = 1,2,3), the proportionality constant (alpha (0 < alpha leqslant 2.2)) occurs due to Jeans’ law, the mass parameter (mu (0 < mu leqslant 1{text{/}}3)), and for the dissipative constant (k (0 < k < 1)). This model has novelty in the sense that we have studied this problem first time by combining the concept of Stokes drag in the restricted four-body problem, considering all primaries as the source of radiation and the fourth body having variable mass. This paper is applicable in various di-sciplines of celestial mechanics as space mission planning, satellite dynamics, and fundamental astrodynamics research. Finally, we have justified the importance of our model by applying it to an appropriate stellar system.

The paper examines the possibilities of using multi-frequency synthesis methods for very long baseline (VLBI) space radio interferometers to improve the ((u,{v})) coverage and the quality of the resulting synthesized images. To evaluate the contribution of multi-frequency synthesis methods, simulations of VLBI observations were performed using the example of the space VLBI concept that is based on a combination of circular near-Earth orbits.