Електронний архів-репозитарій
Одеського національного університету імені І. І. Мечникова
ISSN:2310-7731
Вітаємо на цифровій платформі elONUar, що забезпечує накопичення, систематизацію, обробку, зберігання та надання у відкритий доступ електронних версій наукових, науково-дослідних, навчально-методичних праць та кваліфікаційних робіт наукових та науково-педагогічних співробітників, аспірантів та студентів Одеського національного університету імені І. І. Мечникова, а також електронних версій університетських друкованих видань.
Супровід та підтримка здійснюються Науковою бібліотекою університету
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Нові надходження
Конструкторсько-технологічні рішення акустоелектронних пристроїв фізичних величин на поверхневих акустичних хвилях
(Одеський національний університет імені І. І. Мечникова, 2025) Лепіх, Ярослав Ілліч; Lepikh, Yaroslav I.
В роботі аналізуються існуючі і пропонуються нові конструкторсько-технологічні рішення акустоелектронних пристроїв на поверхневих акустичних хвилях. Відзначається, що при однакових базових елементах пристроїв, в завершальній частині КТР мають місце суттєві відмінності, які запропоновано розглядати як три групи конструкцій корпусування, орієнтовні на серійне (масове) виробництво. Виокремлюються пристрої спеціального призначення, які, як правило, виготовляються малими серіями, а їх конструктив визначається умовами використання в спецапаратурі.
Люмінесцентний сенсор на основі колоїдних нанокристалів оксиду цинку
(Одеський національний університет імені І. І. Мечникова, 2025) Гусейнова, С. Ф.; Берков, Костянтин Євгенійович; Huseynova, S. F.; Berkov, Kostiantyn Ye.
Проведено дослідження впливу іонів важких металів на довгохвильову люмінесценцію колоїдних нанокристалів оксиду цинку. Показано, що додавання іонів кадмію призводить до зростання інтенсивності червоно-жовтої люмінесценції, а свинцю – блакитної. Запропонований механізм роботи сенсора, який пов’язаний з перерозподілом концентрації власних дефектів, що визначають довгохвильову люмінесценцію оксиду цинку.
Preparing radio and optical data for comparing binary black hole candidates: the case of OJ 287
(Одеський національний університет імені І. І. Мечникова, 2025) Zabora, Daniil A.; Ryabov, Mykhailo I.; Sukharev, A. L.; Забора, Данііл Андрійович; Рябов, Михайло Іванович; Сухарев, А. Л.
Background. In light of recent discoveries, in particular the appearance in the literature of strong evidence in favor of a binary supermassive black hole (SMBH) in the core of OJ 287, interest in the search for such objects has revived. Therefore, the issue of detecting candidates has gained considerable relevance. The variability of the radio flux of Active Galactic Nuclei (AGN) in the optical, radio and spatial dimensions provides significant insights into the complex structure of physical phenomena in the immediate vicinity of the black hole and the conditions for launching jets. In particular, these manifestations may indicate the presence of a binary SMBH in the center of such a system.
Data & methods. The paper uses multi-filter optical observations (aggregated by AAVSO) and radio observations of the MOJAVE project at 15 GHz, given in Lister et al. (2019), in the form of radio fluxes and bright component positions (obtained from the VizieR database). Time-frequency analysis methods (including wavelet analysis, LombScargle, and cross-correlation) as well as clustering and regression methods of machine learning and analysis are used for processing.
Results. The intersections of the accretion disk by the companion black hole in the core of OJ 287 cause characteristic optical flares and affect the jet morphology. The latter is manifested in the change in the angles of the bright features (components). It is found that these changes in the case of OJ 287 exhibit noticeable patterns that can be used as indicators for binary black hole candidates (SMBBHs) in active nuclei.
Conclusions. The established connection between optical flares (with potential X-ray verification) and changes in the orientation of jet components with a characteristic pattern can serve as a criterion for detecting binary black hole candidates in AGN.
Illumination of artificial Earth satellites in circular orbits
(Одеський національний університет імені І. І. Мечникова, 2025) Strautman, A.; Bazyey, Oleksandr A.; Страутман, А.; Базєй, Олександр Анатолійович
The purpose of the work is to build an updated model of the illumination of artificial satellites in circular Earth orbits and to study the duration and nature of solar illumination in orbits with different inclinations and altitudes throughout the year.
The mathematical model uses the equation of the circular cone of the shadow, built taking into account the movement of the Sun relative to the Earth. The center of the cross section of the base of the cone coincides with the center of the Earth. The motion of the satellite is simulated by Kepler’s orbit. The computer model makes it possible to determine with a given accuracy the duration of the satellite’s stay in the Earth’s shadow.
Simulation of the duration of illumination of satellites at two altitudes has been performed: 5,000 km and 35,786 km (geosynchronous orbit altitude) throughout the year. Curves of the duration of the satellites’ stay in the shadow are given. The shape of the curves varies from a nearly straight line for inclined orbits 25°, then they become periodic, and then divide into two parts, resembling the shape of a parabola. Among all the possible inclinations of the orbits of satellites, extreme ones have been detected. These are orbits with an angle of inclination 23°26', which defines a straight orbit. On them, an artificial satellite falls into the Earth’s shadow throughout the year at each orbit. The second group of extreme orbits are orbits with inclinations, in which the satellite falls into the shadow only near the time of the equinoxes. Shortest duration of stay of satellites in the shadow moving in orbits with an angle of inclination 113°26'. Falling into the shadow lasts from 15.02 to 23.04 and from 19.08 to 27.10 for an altitude of 5,000 km, and from 12.03 to 28.03 and from 14.09 to 01.10 for an altitude of 35,786 km.
The results of the simulations will allow us to clarify the effect of sunlight and solar wind pressure on the motion of satellites over time. This will allow the use of additional satellite accelerations resulting from radiative impact to change the orbits of space debris and clean up near-Earth space.
Evolution of the rotation parameters of the rocket’s upper stage (space object 1987-074G)
(Одеський національний університет імені І. І. Мечникова, 2025) Koshkin, Mykola I.; Kozhukhov, O.; Shakun, Leonid S.; Bryukhovetskyi, O.; Korobeinikova, Olena O.; Melikyants, Seda M.; Strakhova, Svitlana L.; Dragomiretsky, V. V.; Ryabov, A.; Кошкін, Микола Іванович; Кожухов, О.; Шакун, Леонід Сергійович; Брюховецький, О.; Коробейнікова, Олена Олександрівна; Мелікянц, Седа Мнацаканівна; Страхова, Світлана Леонідівна; Драгомірецький, В. В.; Рябов, А.
Active space debris removal operations require a priori knowledge of the target objects’ rotation parameters, i.e., information on their rotation speed and current orientation in space. This can be achieved through appropriate observations designed to determine these parameters. Recording and subsequent analysis of light curves is the most common method for monitoring space objects’ rotation using optical means. This paper examines the results of long-term photometric observations of a large space debris object — the third stage of the SL-14 rocket (international COSPAR number 1987-074G, USSTRATCOM ID 18340). It shows how this resident space object’s (RSO) rotation speed around its center of mass repeatedly changed between 2006 and 2025. To understand the cause of this behavior of RSO 18340, it is necessary to study the relationship between its different rotation speed states and the corresponding orientation of its rotation axis in inertial space. In paper, we consider the observed light curves of RSO 18340, recorded in 2024 at different observatories, analyze their structure and identify similar photometric patterns in different light curves. These photometric patterns are used to determine the spatial direction of the object’s rotation axis in two short (1–3 days) time intervals in late February – early March 2024. As a result of this analysis of the light curves, four estimates of the average direction of the rotation axis and its evolution over a two-week interval were obtained. Using two light curves obtained during flybys over different observing points on February 27, 2024, we obtained the current direction of the rotation axis in the inertial coordinate system: RA = 10°, Decl. = -66°. And based on six light curves obtained on March 9, 10 and 11, 2024, the following average coordinates were determined: RA = 06°, Decl. = -39°. We estimate the internal error of these results to be ±(5–10)°. Based on these results, we hypothesize that there are no rapid shifts in the rotation axis of RSO 18340.
Determining the orbit of the temporary Earth satellite of asteroid 2024 PT5
(Одеський національний університет імені І. І. Мечникова, 2025) Karastan, Mykyta D.; Bazyey, Oleksandr A.; Карастан, Микита Дмитрович; Базєй, Олександр Анатолійович
This study investigates the gravitational influence of the major planets and the Moon on the orbital dynamics and mechanical energy of near-Earth asteroid 2024 PT5 during its temporary capture by Earth. Discovered on 7 August 2024 by the ATLAS Sutherland survey, the asteroid transitioned onto an elliptical geocentric orbit in late September 2024 and returned to a heliocentric trajectory in mid-November 2024.
The primary objective is to determine which massive bodies of the Solar System specifically the Moon and the nearest planets facilitated the capture process, induced changes in the asteroid’s total mechanical energy during the capture phase, and provided the key perturbations leading to its escape from Earth’s gravitational field. High-precision geocentric ephemerides and osculating orbital elements were obtained from the JPL Horizons service. Numerical analyses of the time series for kinetic, potential, and total mechanical energy, as well as eccentricity, were performed to characterize both the capture and release phases.
Particular attention was given to the temporal correlations between the asteroid’s close approaches to the Moon and to the major planets, and the corresponding variations in its orbital elements. This approach isolates the intervals during which 2024 PT5 experienced the most pronounced dynamical changes, thereby informing targeted numerical simulations. The methodology includes a detailed statement of the problem and computational procedure, including the criteria used to define the start and end of the temporary satellite phase and efforts to identify the bodies exerting the strongest gravitational influence. The results lay the groundwork for developing a general algorithm to assess the probability of capture for any near-Earth object, and to evaluate its potential hazard or scientific value for future sample-return missions. Application of these techniques promises to enhance the precision of asteroid trajectory forecasts and to support ongoing planetary defense initiatives.
3D image of Polaris field stars
(Одеський національний університет імені І. І. Мечникова, 2025) Usenko, Igor O.; Kaliuzhnyi, M. P.; Miroshnichenko, A. S.; Danford, S.; Turner, D. G.; Majaess, D. J.; Balam, D. D.; Усенко, Ігор Олександрович; Калюжний, М. П.; Мірошніченко, А. С.; Данфорд, С.; Тьорнер, Д.; Маджаєсс, Д. Дж.; Балам, Д. Д.
We present a three-dimensional model of the positions of 20 stars in the field of the Cepheid UMi (Polaris) – 18 main sequence stars (spectral types A0–G0 V), the K-giant HD 6319 (K2 III) and Polaris itself (F8 Ib) – which was created using the 3D calculator Desmos 3D, based on the calculated U, V and W components of the full velocity vector of the stars in the Galactic coordinate system. In this paper, stellar radial velocity estimates from Usenko et al. (2023) were used. Two versions of the U, V, and W components were calculated based on Gaia DR3 parallaxes and photometric parallaxes. The resulting 3D image showed that, in both scenarios, 15 main-sequence stars, a K-giant, and Polaris form a noticeable clamp, while three stars (HD 14718, HD 90162, and HD 11696) are located outside of it. HD 14718 and HD 90162 belong to the thick disk, while HD 11696 is a remnant of a possible open cluster in Polaris’s field. The K-giant HD 6319 is located inside the clamp and quite close to the Cepheid, and it is quite possible that this clamp is part of the main component of the probable open cluster Polaris, dissolved in the field of the Cepheid. Using a 3D calculator to construct a spatial image of stars may serve as a good tool for studying the structure and dynamics of open clusters in the future.
Enrichment with the first- and second-peak s-process elements in Galactic disc giants
(Одеський національний університет імені І. І. Мечникова, 2025) Mishenina, Tamara V.; Gorbanova, Tetiana I.; Pignatari, M.; Kurtukian-Nieto, T.; Мішеніна, Тамара Василівна; Горбаньова, Тетяна Іванівна; Піньятарі, М.; Куртукян-Нєто, Т.
The distribution patterns of chemical elements in the Galactic disc remain insufficiently described. In particular, despite considerable attention to the enrichment of disc stars with neutron-capture elements, several questions remain unresolved and warrant further investigation.
In this study, we examine the enrichment of disc stars with first- and second-peak slow neutron-capture (s-process) elements using a sample of 150 Galactic disc giants. Their spectra were obtained with the 1.93-m telescope at the Observatoire de Haute-Provence (France), using the ELODIE echelle spectrograph.
Elemental abundances of the first-peak (Sr, Y, Zr) and second-peak (Ba, La, Ce) s-process elements were determined using synthetic spectrum fitting under the assumption of Local Thermodynamic Equilibrium (LTE). The results were compared with predictions from Galactic Chemical Evolution (GCE) models.
Our findings confirm that the enrichment in both first- and second-peak s-process elements is driven by contributions from both the s-process and r-process, with a possible additional input from other nucleosynthesis sources.
The features of FI Sge photometric variability on Transiting Exoplanet Survey Satellite observations
(Одеський національний університет імені І. І. Мечникова, 2025) Keir, Leonid E.; Panko, Olena O.; Pyatnytskyy, M. Yu.; Кейр, Леонід Едуардович; Панько, Олена Олексіївна; П’ятницький, М. Ю.
We present the result of the analysis of the FI Sge individual light curves constructed on Transiting Exoplanet Survey Satellite (TESS) observations. FI Sge the RR Lyrae pulsating variable star with bicyclicity effects and possible Blazhko effect. In the present study, we analyzed 3603 photometric data obtained by the Transiting Exoplanet Survey Satellite (TESS) in the special TESS IR bandpass with a time resolution of about 10 minutes. The observations covered a 27-day interval (BJD 2459769.90 − 2459796.12) with a small gap of about a day. The full data set contains 52 minima and 51 maxima of the seasonal light curve. We suppose that for this data set, the analysis of the light curve shapes in minima provides more reliable results. We studied the variations of the minima’ shapes of the individual light curves at common and for the separate affinity groups. The last one allowed us to detect not only classical bicyclicity, but also secondary bicyclicity for FI Sge. This result was obtained at first and it is atypical behavior of light curves for pulsating variable stars.
Unistellar eVscope 2: technical specifications, user community, and prospects for application
(Одеський національний університет імені І. І. Мечникова, 2025) Pechko, Anastasiia K.; Panko, Olena O.; Vasylchenko, V. V.; Mirochnik, N. P.; Печко, Анастасія Костянтинівна; Панько, Олена Олексіївна; Васильченко, В. В.; Мірочнік, Н. П.
The Unistellar eVscope2 represents a new generation of compact astronomical instruments that combine portability, automation, and digital networking to empower both professional and citizen astronomers. This study evaluates the telescope’s technical performance, educational potential, and scientific applications, particularly in exoplanet transit photometry. Based on the comparison of our observational data obtained within the Unistellar global network and professional OGLE data, we showed the great possibility of this approach. Our results demonstrate that high-quality light curves can be produced even under sub-optimal conditions, and compact digital telescopes can play an essential role in expanding observational coverage and in training the next generation of astronomers. The Unistellar network model, combining technological innovation, social participation, and data integrity, stands as a powerful example of how future astronomy will operate at the intersection of professional and citizen science.