Kourovka Astronomical Observatory Research Articles

CONFIRMATION OF THE NEW EVOLUTIONARY STATUS OF UU CAS

We present results of a new spectroscopic study of a close binary system with massive components UU Cas based on the spectra obtained with the echelle spectrometer on the 1.2m telescope of the UrFU Kourovka Astronomical Observatory from 2017 to 2022. The results of this study confirm the new evolutionary status of UU Cas previously determined by the author with the spectrophotometry of this system in 2017 and confirmed in a number of works by other researchers. According to these studies, the system is in the final stage of the mass exchange process, but not at its beginning, as previously thought. The components of UU Cas are not very massive, and the ratio of their masses is opposite to a ratio determined earlier from the results of photometry. The parameters of the binary system were obtained on the more extensive observational material. This new parameters differ only slightly from those obtained earlier by the author. The half-amplitudes of the radial velocities are \({{K}_{1}} = 195.6\) km s–1, \({{K}_{2}} = 106.5\) km s–1. The masses of the components are \({{M}_{1}} = 9.6\;{{M}_{ \odot }}\), \({{M}_{2}} = 17.6\;{{M}_{ \odot }}\) for the orbital inclination i = 74.5°. The orbital radius of this close binary is \(A = 54.2\;{{R}_{ \odot }}\). The paper is based on a talk presented at the astrophysical memorial seminar “Novelties in Understanding the Evolution of Binary Stars”, dedicated to the 90th anniversary of Professor M.A. Svechnikov.

Confirmation of the New Evolutionary Status of UU Cas

A new spectral study of the close binary system (CBS) UU Cas with massive components was carried out, based on spectra obtained on the echelle spectrometer of the 1.2-m telescope of Kourovka Astronomical Observatory of UFU from 2017 to 2022. The results of this study confirm the new evolutionary status of UU Cas, previously determined by the author based on spectrophotometry of this system in 2017 and confirmed in a number of works by other researchers, according to which the system is in the final stage of the mass exchange process, and not at its beginning, as previously thought. Its components are not very massive, and the value of their mass ratio is the opposite of what was previously determined from photometry results. The values of the half-amplitudes of the radial velocities \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{K}_{1}} = 195.6$$\\end{document} km/s, \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{K}_{2}} = 106.5$$\\end{document} km/s and the masses of both components \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{M}_{1}} = 9.6\\;{{M}_{ \\odot }}$$\\end{document}, \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{M}_{2}} = 17.6\\;{{M}_{ \\odot }}$$\\end{document} obtained on a much more extensive observational material, for the orbital inclination angle i = 74.5°, given recently in the literature, as well as the orbital radius \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$A = 54\\;{{R}_{ \\odot }}$$\\end{document} of this close binary system are comparable with the values previously found by the author. The article is based on a talk presented at the astrophysical memorial seminar “Novelties in Understanding the Evolution of Binary Stars,” dedicated to the 90th anniversary of Professor M.A. Svechnikov.

History and activities of the Kourovka astronomical observatory of the Ural university

The history of origin and scientific activities of the suburban Astronomical Observatory of the Ural University are associated with K.A. Barkhatova’s life and work, among her achievements were restoration of the Department of Astronomy and Geodesy in 1960, and the resumption of the training of specialists in astronomy and geodesy. The First satellite launch on October 4, 1957 was great stimulus for the opening of department. A station for optical observations of satellites was organized in Sverdlovsk. Successful scientific and academic work of the department required a modern, properly equipped suburban observatory. Yu.A. Gagarin flight around the Earth on April 12, 1961 aroused unprecedented interest in astronomy and space among people and accelerated the resolution of the issue of an observatory construction. K.A. Barkhatova, with the support of colleagues from the Astronomical Council of the USSR Academy of Sciences, other observatories of the country, rector of the Ural University, and the public took up the construction. In 1963 the observatory near Kourovka station was founded. January 12, 1965 is considered to be the birthday of the new observatory. K.A. Barkhatova was it’s scientific adviser; at present, the observatory is named after her. The observatory performs observations on modern equipment, conducts excursions for students, teachers and public. Each year, the observatory hosts a student scientific conference "Physics of Space" – a unique astronomical school for young students and graduate students.

Contribution of the student conferences “Physics of Space” to the continuing astronomy education system

AbstractUral Federal University is one of the main and most effective centers for educating young astronomers in Russia. The traditional student scientific conferences “Physics of Space” have been successfully held annually in Kourovka Astronomical Observatory of the Ural Federal University for 50 years and have gained recognition not only in Russia. The conference initiated many educational initiatives both in the Ural region and, in general, in Russia. The astronomy education system implemented by UrFU and partners includes the following activities: 1) education and career guidance of schoolchildren in the Lyceum of UrFU, 2) activities to attract applicants, 3) training at the speciality, undergraduate, and graduate level, 4) participation in the student conferences “Physics of Space”, 5) postgraduate studies, 6) cooperation in the field of education. This activity ensures the attraction of promising youth to scientific research.

On the Gas Dynamic Features of the Interacting Binary System UU Cas

Abstract We present the results of spectroscopic observations and Hα Doppler tomography of the massive close binary system UU Cas where a giant star fills its Roche lobe (donor) and transfers material through the vicinity of the L 1 point onto a massive but rather compact stellar companion (accretor). The system has been observed at the 1.2 m telescope of the Kourovka Astronomical Observatory. By analyzing the obtained spectra and computed Doppler tomogram, we suggest that at least three elements of the gas dynamic pattern in the system contribute to the Balmer Hα emission line profiles. These elements are: the stream from the L 1 point, the stellar wind from the accretor, and the diffuse disk, surrounding the accretor. In combination with the estimates of the companions’ masses, our findings indicate that the system is at the late stage of the first mass transfer phase of its evolution.

Variability of emission lines in the optical spectra of the Herbig Be binary system HD 200775

In our previous papers we have improved the value of the orbital period of the binary Herbig Be star HD 200775 and showed that the [O I] and Si II 6347 and 6371 Å emission lines displayed variations which correlate with the orbital period. In this paper we provide evidences that other broad emission lines of metals in the spectra of HD 200775 also exhibit variability, which is probably related to the orbital cycle of the binary. Analysis was performed based on the high-resolution spectral data collected over a time span of 6 years at the Kourovka Astronomical Observatory of the Ural Federal University (Russia) and the Three College Observatory of the University of North Carolina at Greensboro (USA) as well as archival spectral data compiled since 1994. We report new data points in the radial velocity curve of the He I 5876 Å line near the extremal values of the radial velocity.

Photospheric Spots and Flare on the Active Dwarf Star FR Cnc

We perform analysis of new BVRI photometry of young active dwarf star FR Cnc (K7V), obtained at Kourovka astronomical observatory of Ural Federal University with the help of multichannel electrophotometer in February 2010. The lightcurve displays sinusoidal rotation modulation with the amplitude of 0m.15 in V band. Reddening of the brightness at the photometric minimum confirms that this modulation is caused by cold photospheric spots. An analysis of the spottedness distribution in terms of a zonal model based on our own and published data shows that the spots are localized at lower and middle latitudes from 47° to 56°, occupy 10-21% of the star’s area, and are colder than the photosphere by 1650 K. A flare was detected on February 3, 2010, at a time corresponding to HJD=2455231. 3136. A maximum amplitude of 0m.11 was observed in the B band, the amplitudes in the V, R, and I bands were 0m.04, 0m.03, and 0m.02, respectively, and the duration of the flare was 32.5 min. It was noted that the flare occurred near the maximum spottedness of the star. The calculated total energy of the flare was 2.4·1033 and 1.3·1033 erg in the B and V bands, respectively. The flare was found to have an afterglow, with an overall increase in the star’s brightness by 0m.02 in the B band after the flare compared to the pre-flare level.

Eclipsing binary UU Cas: Radial-velocity curves

This paper reports the results of spectroscopic observations of UUCas obtained with the highresolution (R = 15 000) fiber-fed echelle spectrometer of the 1.2-m telescope of Kourovka Astronomical Observatory of Ural Federal University. The radial velocities of the secondary, more massive and fainter component are measured for the first time. The component mass ratio is found to be q = M 1/M 2 = 0.54. The component masses, M 1 = 9.5M ⊙ and M 2 = 17.7M ⊙, and the radius of the or bit, A = 52.7R ⊙, are computed for the published orbital inclination of i ~ 69°. Evidence is presented for a disk surrounding the more massive component and a common expanding envelope.

Positional observations of small solar system bodies with the SBG telescope at the Astronomical Observatory of the Ural Federal University

The telescope SBG (D = 0.42 m, F = 0.76 m) at the Kourovka Astronomical Observatory of the Ural Federal University has undergone an upgrade in 2005–2006. A CCD camera (Apogee Alta U32) and a new drive system were installed, and a new system for telescope and observation control was implemented. This upgrade required verifying the astrometric quality of the telescope. The data processing approaches tested when searching for the optimum CCD image processing technique combined TYCHO2 and UCAC2 catalogues with various reduction models and methods for choosing reference stars. Lorentzian and Moffat profiles were used in the measurement of pixel coordinates. It was demonstrated that the accuracy of SBG observations of main-belt asteroids with precisely determined orbits depends on their brightness and varies from 0.06” (11.5 m ) to 0.4” (18.5 m ). Regular SBG observations of comets and asteroids (mostly near-Earth and potentially hazardous ones) have been performed since 2007. Coordinates of 8515 positions of 720 asteroids and more than 1000 positions of 40 comets were obtained. The RMS deviations of observed coordinates from their calculated values are typically smaller than 1”: the average deviations for asteroids are 0.33” (in right ascension) and 0.34” (in declination); the corresponding values for comets are 0.37” (in α) and 0.38” (in δ). The results of observations are sent to the Minor Planet Center and are used to determine orbits more accurately and solve other fundamental and applied problems.

Alerting observations of asteroids at the SBG telescope of the Kourovka Astronomical Observatory in the Gaia-FUN-SSO Network

AbstractRegular astrometric observations of small bodies of the Solar System are conducted using a SBG telescope of the Kourovka Astronomical Observatory of the Ural Federal University. The first results of participation in Gaia-FUN-SSO network are presented.

First results of the Kourovka Planet Search: discovery of transiting exoplanet candidates in the first three target fields

We present the first results of our search for transiting exoplanet candidates as part of the Kourovka Planet Search (KPS) project. The primary objective of the project is to search for new hot Jupiters which transit their host stars, mainly in the Galactic plane, in the $R_c$ magnitude range of 11 to 14 mag. Our observations were performed with the telescope of the MASTER robotic network, installed at the Kourovka astronomical observatory of the Ural Federal University (Russia), and the Rowe-Ackermann Schmidt Astrograph, installed at the private Acton Sky Portal Observatory (USA). As test observations, we observed three celestial fields of size $2\times2$ deg$^2$ during the period from 2012 to 2015. As a result, we discovered four transiting exoplanet candidates among the 39000 stars of the input catalogue. In this paper, we provide the description of the project and analyse additional photometric, spectral, and speckle interferometric observations of the discovered transiting exoplanet candidates. Three of the four transiting exoplanet candidates are most likely astrophysical false positives, while the nature of the fourth (most promising) candidate remains to be ascertained. Also, we propose an alternative observing strategy that could increase the project's exoplanet haul.

Spectrometric and photometric study of the eclipsing variable AM Leo

The results of quasi-simultaneous spectroscopic and photometric observations of a W UMatype eclipsing variable star AM Leo are presented. The observations were carried out with a 1.2-m telescope equipped with a high-resolution echelle spectrometer, and a telescope-reflector (D = 0.45m) of the Kourovka Astronomical Observatory of Ural Federal University. New values of semi-amplitudes of the radial velocity curves of the components, K 1 = 109.6kms−1 and K 2 = 252.4kms−1 and the systemic radial velocity V 0 =-9.3 kms−1 are obtained, comparable to the data published in the literature. The semi-amplitude of the radial velocity curve of a more massive component K 1 and the mass ratio of the components q = 0.412 appeared to be slightly smaller than the values obtained by other authors. An assumption wasmade that a possible reason of this is the presence of hot and/or cold spots on the surface of the components, shifting the effective center of brightness of the visible disk of the component with respect to its center of mass position. It was shown that the AM Leo light curve variations on the time scales of one and more days, registered within the photometric part of the study may be described by the choice of appropriate model of the spot structure.

Optical spectroscopic monitoring of the Herbig Be binary star HD 200775: New maximum of activity and refinement of the orbital period

We refined the orbital period of the Herbig Be binary star HD200775 using both new and archive observed data which has been obtained with high-resolution spectrometers at optical wavelengths over 20 years. The new spectroscopic observations were performed with the 1.2-m telescope of the Kourovka Astronomical Observatory of Ural Federal University during 2012–2014 and the 6-m BTA telescope of the Special Astrophysical Observatory in 2013.We show that the period of these observations has a new maximum of activity in 2012 and the following transition of the star to the quiescent state. We confirmed that activity maxima of HD200775, which are characterized by the increase of the Hα equivalent width, appear at intervals of about 3.7 years. A stable orbital period of the system of \(1361_.^d 3 \pm 2_.^d 2\) days was found from radial velocity variations obtained for the He I 5876 A line. It is shown that the radial velocities determined from the Hα emission line and the He I 5876 A absorption line, which is formed in the photosphere of the more massive primary component of the system, are close and change synchronously with time. This synchronization indicates the fact that the major portion of the HD200775 Ha emission originates in the material associated with the more massive component of the system.

Effect of the high-order resonances on the orbital evolution of objects near geostationary orbit

The area-to-mass ratio of high-orbit space objects is estimated on the basis of positional observations from the SBG telescope at the Kourovka astronomical observatory of the Ural Federal University. The properties of regions where high-order resonances are located are analyzed. The position and sizes of the resonance zones depending on the area-to-mass ratio of objects are determined on the basis of numerical modeling. It is shown that a system transits through the high-order resonances due to secular perturbations of the semimajor axis under the Poynting-Robertson effect. The high-order resonances weakly influence the formation of the stochastic trajectories. The stochastic properties are mostly manifested in evolution of the semimajor axis of the orbit.

Upgrade of the fiber-fed spectrograph of the Kourovka Astronomical Observatory

We report the results of testing the high-resolution fiber-fed spectrograph of Kourovka Astronomical Observatory of the Ural Federal University in 2010–2012 and the corresponding operation experience, and demonstrate the need for an upgrade of the instrument. We also describe the modifications that were made to the design of the spectrograph during the start of its regular operation in 2010 and the refurbishment of its suspended part carried out in 2013, which allowed to expand the capabilities of the instrument.

Astrokit-an efficient program for high-precision differential CCD photometry and search for variable stars

Having a need to perform differential photometry for tens of thousands stars in a several square degrees field, we developed Astrokit program. The software corrects the star brightness variations caused by variations of atmospheric transparency: to this end, the program selects for each star an individual ensemble of reference stars having similar magnitudes and positions in the frame. With ten or more reference stars in the ensemble, the differences between their spectral types and the spectral type of the object studied become unimportant. Astrokit searches for variable stars using Robust Median Statistics criterion, which allows candidate variables to be selected more efficiently than by analyzing the standard deviation of star magnitudes. The software allows very precise automatic analysis of long inhomogeneous sets of photometric observations of a large number of objects to be performed, making it possible to find "hot Jupiter" type exoplanet transits and low-amplitude variables. We describe the algorithm of the program and the results of its application to reduce the data of the photometric sky survey in Cygnus as well as observations of the open cluster NGC188 and the transit of the exoplanet WASP-11 b / HAT-P-10 b, performed with the MASTER-II-URAL telescope of the Kourovka Astronomical Observatory of the Ural Federal University.

Continuous measurements of atmospheric water vapour isotopes in western Siberia (Kourovka)

Abstract. The isotopic composition of atmospheric water vapour at the land surface has been continuously monitored at the Kourovka astronomical observatory in western Siberia (57.037° N, 59.547° E; 300 m a.s.l.) since April 2012. These measurements provide the first record of δD, δ18O and d-excess in this region. Air was sampled at 8 m height within a forest clearing. Measurements were made with a wavelength-scanned cavity ring-down spectroscopy analyzer (Picarro L2130-i). Specific improvements of the measurement system and calibration protocol have been made to ensure reliable measurements at low humidity during winter. The isotopic measurements conducted till August 2013 exhibit a clear seasonal cycle with maximum δD and δ18O values in summer and minimum values in winter. In addition, considerable synoptic timescale variability of isotopic composition was observed with typical variations of 50–100‰ for δD, 10–15‰ for δ18O and 2–8‰ for d-excess. The strong correlations between δD and local meteorological parameters (logarithm of humidity and temperature) are explored, with a lack of dependency in summer that points to the importance of continental recycling and local evapotranspiration. The overall correlation between δD and temperature is associated with a slope of 3‰ °C−1. Large d-excess diurnal variability was observed during summer with up to 30‰ decrease during the night and the minima manifested shortly after sunrise. Two dominant diurnal cycle patterns for d-excess differing by the magnitude of the d-excess decrease (21‰ and 7‰) and associated patterns for meteorological observations have been determined. The total uncertainty of the isotopic measurements was quantified as 1.4–11.2‰ for δD, 0.23–1.84‰ for δ18O and 2.3–18.5‰ for d-excess depending on the humidity.

Orbital and physical parameters of the spectroscopic binary HD37737

We report the physical and orbital parameters of the visible component of the spectroscopic binary HD37737 (m V = 8.03). The observations were performed with the 1.2-m telescope of the Kourovka Astronomical Observatory of the Ural Federal University in 2012 and the 6-m BTA telescope of the SAO RAS in 2007 and 2009. Radial velocities were measured separately from each spectral line of the list by the cross-correlation method with a synthetic spectrum. The latter was calculated using the grids of non-LTE model atmospheres with solar chemical compositions. A significant difference in the epochs of observations (2005–2012) allowed to refine the orbital period of the star (7 · d 84705) and the orbital elements of the binary system. We obtained an estimate of the mass function f(m) = 0.23 ± 0.02M ⊙. The best agreement between the synthetic and observed spectra is achieved at T eff = 30 000 K and log g = 3.50 according to the observations on both instruments. The obtained parameters correspond to a star of spectral type O9.5 III, with mass estimated at 26 ± 2M ⊙. The minimum mass estimate of the secondary component of the binary is 6.2 ± 0.5M ⊙. We have discovered a fact that the velocities, obtained from different spectral lines, differ, which is typical for giant stars. Engaging additional spectra, obtained in 2005 with the 2.1-m KPNO telescope, we investigated the effect of this fact on the estimate of the speed of the system’s center of mass. The difference in the velocities of various lines is approximately the same in the spectra, obtained at all the three instruments. The obtained ratios suggest that the deeper layers of the atmosphere of the star are moving with a greater velocity than the outer layers. Depending on the line, the estimate of the heliocentric velocity of the binary’s center of mass varies in the range from −11 to 1 km/s.

Trajectory retrieval and component investigations of the southern polar stratosphere based on high-resolution spectroscopy of the totally eclipsed moon surface

In this paper we present the high-resolution spectral observations of the fragment of lunar surface during the total lunar eclipse of December 10, 2011. The observations were carried out with the fiber-fed echelle spectrograph at the 1.2-m telescope in Kourovka Astronomical observatory (Ural mountains, central Russia). The observed radiation is transmitted by tangent trajectory through the southern polar stratosphere before the reflection from the Moon and the spectra contain a number of absorption bands of atmospheric gases (O2, O3, O4, NO2, H2O). High-resolution analysis of three O2 bands and O4 absorption effects is used to trace the effective trajectory of solar emission through the stratosphere and to detect the contribution of scattered light. Bands of other gases allow us to measure their abundances along the trajectory.

Light pressure effect on the orbital evolution of objects moving in the neighborhood of low-order resonances

The hardware-software complex of the SBG telescope of the Kourovka astronomical observatory of the Ural Federal University is described. The area-to-mass ratio of high-orbit objects was estimated from the results of positional observations at the SBG telescope. Positions and sizes of resonance zones are determined from the numerical simulation results depending on the area-to-mass ratio in the case of low-order resonances (1 : 1, 1 : 2, and 1 : 3). Secular perturbations of semimajor axes of orbits, caused by the Poynting-Robertson effect, are estimated in the neighborhood of low-order resonance zones at different area-to-mass ratios.