В Кисловодcкой обсерватории ИНАСАН на плато Шаджатмаз начались регулярные наблюдения на фотометриче- ском комплексе для исследования транзитов экзопланет, построенном на основе телескопа Астросиб RC500 с при- емником излучения ZWO ASI6200MM Pro и колесом фильтров UBVRI. В конце 2023 и начале 2024 г. проведены наблюдения 10 транзитов экзопланет и одного кандидата в затменные переменные с пульсирующим компонентом 2MASS J23453766+713436. Проведены оценки максимальной проницающей величины фотометрического комплекса. При экспозиции 120 с в фильтрах R и V с SN R = 20 уверенно обнаруживаются объекты 19 m . При экспозициях 90 с в фильтрах V и R при SN R = 10 зафиксированы объекты 18.2 m и 19 m , соответственно. В идеальных услови- ях (нет облаков, дымки, ветра, хорошее качество изображений) для звезд с R = 13 m достигается точность (RMS) 3.5–4.0 mmag. Для более ярких объектов (R = 11 m ) достигается точность около 1.0 mmag при усреднении измерений с шагом 3 мин. Индивидуальные измерения имеют точность около 1.9 mmag. Regular observations started on photometric complex for studying exoplanet transits, located at the Kislovodsk Observatory of INASAN on the Mount Shatdzhatmaz. Its construction is based on the Astrosib RC500 telescope equipped with a ZWO ASI6200MM Pro camera and a UBVRI filter wheel. At the end of 2023 and the beginning of 2024, observations of 10 transits of exoplanets and 2MASS J23453766+713436, the eclipsing variable with a pulsating component candidate, were carried out. The maximum apparent magnitude of the photometric complex has been estimated. Objects of 19 m are reliably detected with SN R = 20 at the exposure of 120 sec in filters R and V. At exposures of 90 s in filters V and R objects of 18.2 m and 19 m respectively were recorded with SN R = 20.

The results of new photometric observations of the chromospherically active star ET Dra, performed using telescopes of the Zvenigorod INASAN Observatory, the Russian-Cuban Observatory in the territory of the Republic of Cuba (Havana), and the Terskol INASAN Observatory (a total of 8 sets of observations) with the addition of archival observations of the Kamogata Wide-field Survey. Variations in the shape of the light curve caused by the rotational modulation of a star with spots on the surface, as well as studies of the long-term variability of the star’s brightness, were investigated based on the data acquired in 2018–2023. Characteristic changes in the ET Dra light curve were noted including a decrease of the stellar brightness in the V filter, its cyclic variations, and subsequent brightness increase. The shape of the phase curve and the duration of the extended minimum of brightness vary. During the HJD 245 9670–245 9715 interval, the amplitude of the star’s brightness variability reached a maximum value of more than 0.4m, as it was in 1990. The surface temperature inhomogeneities maps were calculated and estimates of the spottedness parameter S of the object were performed for each of the 8 sets of observations. Maximum value of parameter S was 32.2‒33.5

A method for increasing the glass transition temperature of the compositions obtained by curing an epoxy-diane resin with a partially siloxy-substituted organo(alkoxy)(zirconium)siloxane by introducing phenylsiloxane resins is considered. The initial content of zirconium siloxane was 10 wt %. It is shown that the introduction of the siloxane resins in 10–50 wt % relative to the epoxy resin is capable of not only increasing the glass transition temperature of the material almost twice, but also enhancing the curing degree of the system.

The results of measurements of background brightness in the near-infrared range (J, H, K bands), carried out in 2016–2023 at the Caucasus Mountain Observatory of Moscow State University was analyzed. It is shown that the instrumental background associated with the thermal radiation of the telescope is noticeable only in the K band, and at operating temperatures its contribution mainly determines the level of the overall background in this band. The coefficients of a polynomial taking into account the contribution of instrumental and extra-atmospheric backgrounds are presented. It is shown that the brightness of the sky background does not depend on air temperature, but a weak dependence on the water vapor content is observed, close to that expected from model calculations: in the J and H bands, the background brightness decreases at a rate of ≈ 1pt 1%/1 mm, and in the K band it grows at a rate of ≈ 1pt 2.5%/1 mm. The maximum amplitude of background brightness variability on short time scales ( ∼ 1pt 30 min) has been estimated: ≈ 1pt 10 J and K bands and ≈ 1pt 30 H band. The maximum contribution of Moon’s radiation scattered in the atmosphere to the overall background level has been determined. It is shown that this contribution can be ignored at an angular distance from the Moon greater than ∼ 1pt 10^∘ even during a full moon. The average background surface brightness mag/arcsec2 in the J, H, and K bands was calculated: m_J = 15.7 , m_H = 13.9 , and m_K = 13.1 .

В статье обсуждается стратегия и методика поиска экзопланет в рассеянных скоплениях на роботизированных теле- скопах ИНАСАН транзитным методом. Из-за высокой звездной плотности и расположению вблизи плоскости Галак- тики рассеянные скопления не всегда могут успешно наблюдаться космической миссией TESS, однако могут быть легко исследованы на небольших наземных телескопах. В рамках нашей программы мы проводим фотометрический мониторинг избранных площадок в близких рассеянных скоплениях на роботизированном телескопе Astrosib RC500. В результате обработки планируется выявить звезды-кандидаты, демонстрирующие периодические вариации блес- ка, по форме и амплитуде соответствующие транзитам экзопланет. В случае обнаружения таких кандидатов будет развернута программа подтверждения путем фотометрических, спектроскопических и спекл-интерферометрических наблюдений на российских телескопах. Также в результате реализации программы будут исследованы уже известные переменные звезды наблюдаемых скоплений и обнаружены новые. In this paper we discuss the strategy and methodology of searching for exoplanets in open clusters on INASAN robotic telescopes using the transit method. Due to the high stellar density and location near the galactic plane, open clusters cannot always be successfully observed by the TESS space mission, but can be easily studied with small ground-based telescopes. As part of our program, we conduct photometric monitoring of selected fields in nearby open clusters on the Astrosib RC500 robotic telescope. As a result of processing, it is planned to identify candidate stars demonstrating periodic brightness variations, corresponding in shape and amplitude to exoplanet transits. If such candidates are found, a confirmation program will be launched by photometric, spectroscopic and speckle interferometric observations on Russian telescopes. Also, as a result of the program implementation, already known variable stars of the observed clusters will be studied and new ones will be discovered.

Космический аппарат Transiting Exoplanet Survey Satellite (TESS) получил большое количество высокоточных фото- метрических данных, которые можно использовать для решения огромного количества астрономических задач. Но точности и полноты данных, предоставляемых открытым архивом данных TESS, не всегда достаточно для их реше- ния. Поэтому, мы представляем простой, но мощный конвейер на основе пакетов Lightkurve и Astrobase для обработки и анализа сырых данных TESS. Мы также приводим краткий обзор наших исследований, в которых мы используем данные TESS, проанализированные с помощью этого конвейера. Мы проводим программу поиска и подтверждения переменных звезд с использованием архивов кадров малых фотометрических телескопов Астрономического инсти- тута им. П. К. Штернберга (ГАИШ) и Института астрономии РАН (ИНАСАН), в которой используем высокоточную фотометрию TESS и обзора ZTF. Мы также проводим картирование хромосферно-активных звезд, используя кривые блеска, полученные из необработанных данных TESS с помощью нашего конвейера. Также мы приводим фотометрию карликовых новых и других транзиентных астрономических объектов на основе нашей обработки данных TESS. Transiting Exoplanet Survey Satellite (TESS) spacecraft obtained a large amount of high-precision photometric data, which can be used to solve a huge number of astronomical problems. But the accuracy and completeness of the data provided by the TESS open data archive is not always enough to solve them. So we present simple but powerful pipeline based on Lightkurve and astrobase, for raw TESS data reduction and analysis. We also present a short overview of our research in which we use TESS data, analysed using this pipeline. We are conducting a program to search and confirm variable stars using archives of frames from small photometric telescopes of Sternberg Astronomical Institute (SAI) and Institute of Astronomy of the Russian Academy of Sciences (INASAN), in which we use high-precision photometry of TESS and Zwicky Transient Facility (ZTF). We also conduct mapping chromospherically active stars using light curves extracted from raw TESS data by our pipeline. We also present photometry of dwarf novae and other transient astronomical objects based on our processing of TESS data.

The possibility of application of carboxy- and thioether-containing alkoxysilanes as additives in the formation of elastomeric SiO2-filled polydimethylsiloxane (PDMS) compositions cured with zirconium siloxanes has been studied. It is shown that the introduction of these additives into the system ensures an increase in the dielectric constant, provided that the final components are compatible (up to ε' ≥ 4 at f =102 Hz). By varying the composition and initial ratio of the components, it is possible to achieve the desired mechanical characteristics suitable for using the resulting materials as actuators.

The catalytic activity of a wide range of metals incorporated into the structures of metallosiloxane oligomers in the curing process of epoxy-diane resins has been estimated. From the viewpoint of activity, the most preferable metallosiloxanes are those containing Al, Hf, and Nb, and from the viewpoint of cost—Al, Ti, FeII, Zr. It is shown that the structure and functionality of the metallosiloxane can serve as the factors to control the formation of a metallosiloxane–epoxy material, which allows for increasing the efficiency of metal catalysis.

We present the algorithm of exoplanets transit search in MASTER global robotic telescope network database, that has been created with the involvement and use of artificial intelligence methods. MASTER’s 2003–2023 years archive images are stored at data storage and analysis center in Lomonosov supercomputer. For exoplanets transit search we used the images of SWIFT gamma-ray bursts alerts (GRB), received by MASTER telescopes during several hours at target nights. The algorithm includes cross-correlation of GRB error-boxes coordinates and TESS exoplanetary transits candidates inside 4 square degrees of each field. Our analyses is based on wide-field images obtained on MASTER-Amur, -Tunka, -Kislovodsk, -Tavrida, MASTER-IAC, MASTER-OAGH, MASTER-OAFA and MASTER-SAAO robotic telescopes. We used data storage and analysis center in Lomonosov supercomputer with MASTER images archive, calculated light curves for target stars and approximate them to find eclipse by exoplanets. The centralized storage of this data allows us to simplify and significantly speed up access to the huge archive of images formed during the entire operation of the robotic network for automatic processing and facilitate the manual search for the necessary information by the researcher. From this storage we compared the program with unique long homogeneous series of Swift GRBs alert and inspection observations, which we analyzed. The main result is reduction of unique light curves of exoplanetary transits of TIC 127115861.01 TESS candidate, obtained by MASTER long before the TESS space observatory.

Мы представляем исследование карликовой новой TCP J18173469+1803499. Она была обнаружена во время широ- копольного обзора New Milky Way (NMW) на Астроферме Астроверты, и в течение 9 ночей мы выполняли фото- метрический мониторинг этого объекта в полосах BVRI с помощью нового 50-см роботизированного телескопа Кис- ловодской обсерватории ИНАСАН. Были обнаружены сверхгорбы с периодом 0.0592 суток, которые имели малую амплитуду в начале вспышки, но на 9 сутки после начала вспышки приобрели большую амплитуду и симметричную пилообразную форму. Мы проанализировали фотометрическое поведение TCP J18173469+1803499 по результатам наших наблюдений. Наличие сверхгорбов и амплитуда вспышки, составляющая более 8 звездных величин позволяют отнести этот объект к карликовым новым типа WZ Sge. We present analysis of a dwarf nova TCP J18173469+1803499. It was discovered during the New Milky Way (NMW) wide-field survey at Astroverty astrofarm, and during 9 nights we performed photometric monitoring of this object in BVRI bands with a new 50-cm robotic telescope of Kislovodsk observatory of the Institute of Astronomy of the RAS. We detected superhumps with a period of 0.0592 days, with a small amplitude at the beginning of the outburst. However, on the 9th day after the start of the outburst they acquired a large amplitude and a symmetrical sawtooth shape. We analyzed the photometric behavior of TCP J18173469+1803499 based on our observations. The presence of superhumps and a flare amplitude of more than 2 magnitudes allow us to classify this object as a dwarf nova of the WZ Sge type.

The paper presents the method for detecting exoplanets in the image archive obtained by telescopes of the MASTER Global Network since 2002. The unique archive represents homogeneous photometric data obtained over 20 years for the northern (MASTER-Amur, MASTER-Tunka, MASTER-Kislovodsk, M-ASTER-Tavrida, MASTER-IAC, MASTER-OAGH) and 11 years for the southern sky (MASTER-OAFA, MASTER-SAAO). Algorithm of gamma-ray burst error box observation on the MASTER wide-field telescopes make it possible to detect transit phenomena and find exoplanets in archival data. The article presents the results of a photometric analysis of the TESS exoplanet candidate TOI–3570.01.

A number of thioether-containing zirconium siloxanes, differing in their composition and metal atom shielding degree with a siloxy substituent, were synthesized and characterized. Synthesis of such compounds made it possible to evaluate the effect of sulfur atoms’ presence in the cured compositions on their dielectric properties, as well as to evaluate their curing ability and influence on mechanical characteristics compared to the sulfur-free analogs obtained earlier. Studying a wide range of compositions differing in their content and ratio of metallosiloxane and silica components revealed that such systems are still typical dielectrics. At the same time, the introduction of thioether groups can provide increased dielectric constant and conductivity in comparison with previously obtained sulfur-free similar compositions in the <102 Hz frequency range (dielectric constant up to ~10–30 at frequency range 1–10 Hz). As before, the dielectric parameters increase is directly determined by the silica component proportion in the cured material. It is also shown that varying sulfur-containing zirconium siloxanes structure and functionality and its combination with previously obtained sulfur–free analogs, along with varying the functionality and rubber chain length, can be an effective tool for changing the dielectric and mechanical material parameters in a wide range (tensile strength 0.5–7 Mpa, elastic deformation 2–300%), which determine the prospects for the use of such cured systems as dielectric elastomers for various purposes.

We report the results of optical spectroscopy of eight highly variable X-ray sources—AGN candidates from all-sky survey of the eROSITA telescope of the Spectrum-Roentgen-Gamma Space Observatory—performed with the TDS spectrograph (3600–7500 Å, R≈ 2000 ) attached to the 2.5-m telescope of the Caucasian Mountain Observatory of Sternberg Astronomical Institute of M.V. Lomonosov Moscow State University. We determined the redshifts of the sources from the emission and absorption lines in their spectra. At least five objects can be classified as Seyfert galaxies. We performed pilot infrared photometry of three distant quasars with z>5 using the ASTRONIRCAM camera and show that on the ‘‘ (z-J)-(J-W1) ’’ diagram the distant quasars studied can be confidently distinguished from Galactic red and brown dwarfs. This result proves the possibility of preliminary classification of distant X-ray quasar candidates by their IR colors for further detailed spectroscopic study on large telescopes.

We obtained a unique series of photometric data for more than a hundred years for a rapidly rotating single G5 III–IV giant HD 199178 (V1794 Cyg), belonging to FK Com type stars. The analysis of the long-term variation of the activity of this star in the filter B is based on all measurements available in literary sources. To evaluate the brightness of HD 199178 in the era preceding photoelectric and CCD-observations, the measurements of photographic plates from the SAI MSU archive were shot at the Krasnopresnenskaya Observatory of Moscow State University in Moscow (4 records shot from 1898 to 1903, and 41 records for the period from 1935 to 1958) were performed. As a result, a total of 2142 assessments of the brightness of the star in the filter B were received. They have a unique duration of 118.3 yr and cover the time interval from 1898 to July 2016. Evidence was found of the existence of long-term cycles of photometric variability lasting for about 25‒60 years. We put forward an assumption on existence of possible activity cycles of 2000, 3165, 5050, 9000, and 21 600 d (respectively, 5.5, 8.7, 16.6, 24.7, and 59.2 years). The results are compared with other estimates of activity cycles in HD 199178. The most reliable should be recognizing the existence of a cycle lasting 8.7‒9 years. It was found that in order to combine data into a single array, the convertation of B magnitudes into V magnitudes using the average value of the color index ( B – V ) is not possible due to the changes (including cyclic) of color index ( B – V ) over time.

The dielectric and mechanical properties of a wide range of polydimethylsiloxane-based compositions filled with silica component and cured with various metallosiloxanes have been studied. It is shown that the resulting systems are typical dielectrics. Silica component introduction in combination with the metal-siloxane network formation in the material can significantly increase its dielectric permittivity and conductivity in the frequency range <10(2) Hz compared to commercial silicon compounds and pure PDMS. It is found that varying the metallosiloxane structure and composition and the degree of silica filling are effective tools for changing the dielectric parameters of the material - up to similar to 5-10 at 1-10 Hz. By varying the functionality and length of the rubber chain, as well as the curing rate, it is possible to vary the mechanical properties of the material within a wide range - 2-10 MPa strength and elongation up to 500% with the pure elastomeric properties up to 200%. This approach to the formation of material opens up prospects for using such cured systems as dielectric elastomers for special applications such as flexible capacitive sensors or actuators for medical and robotic applications.

This article presents a synthesis of stable guanidine-containing alkoxysilyl derivatives based on the synthesis procedure through amino derivatives and ylide of thiourea suggested previously. Amino- and mercapto-containing siloxane oligomers were synthesized by hydrolytic co-condensation based on the silanes thus obtained, and the biocidal activity of their aqueous solutions in comparison with the starting monomers was studied. The prospects of using the resulting compounds as biocidal additives to epoxy compositions and a high biocidal activity at their small concentrations in the cured material against S. aureus, E. coli, and C. albicans strains were demonstrated.

In this work, the curing of << ED-20 >> epoxy resin with partially siloxy-substituted aluminum, iron, and zirconium siloxanes that we obtained previously was studied. The initial content of a metallosiloxane in the compositions was 5-50 wt% with respect to the resin. In all the cases, thermal curing was used to obtain a series of samples in the form of solid homogeneous materials. The fact of the epoxy ring opening in the resin was confirmed by IR spectroscopy. The catalytic properties of the metal atom in a metallosiloxane were found to affect the curing process. The samples demonstrate rather a high resistance to thermooxidative destruction, and in most cases, their glass transition temperatures are lower than those obtained upon standard curing of << ED-20 >> resin with triethylenetetramine. Partially siloxy-substituted metalloalkoxysiloxanes can be efficient agents for curing and formation of a hybrid material based on epoxy resins.

A synthetic process for new functional metallosiloxanes containing M-OEt groups (where M is metal) has been developed. Compounds of iron, aluminum and zirconium were obtained by the interaction of a corresponding metal chloride with a mixture of sodium organoalkoxysilanolate and sodium ethylate in a ratio that makes it possible to preserve and adjust the number of functional groups at the metal atoms. A process of partial hydrolysis of functional metallosiloxanes and a possibility of using the products obtained as a binder in compositions based on silicone rubber have been investigated. It has been shown that such compounds can be used as cross-linking agents in silicone rubber compositions.

For the first time, diacid derivative of limonene was obtained by thiol-ene reaction with mercaptoacetic acid and it was further used as a monomer for the synthesis of polyamides. Commercially available hexamethylenediamine and its siloxane analogue, bis(aminopropyl) tetramethyl disiloxane, were used as diamines monomers. It was shown that the introduction of a siloxane unit into the structure of a polyamide chain increases the molecular weight and thermal stability of the polymer (more than 300 degrees C), and also affects its phase behavior at room temperature.