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Article
Open AccessDistribution of Cool Starspots on the Surface of the Red Dwarf V647 Her
An analysis of photometric observations of the star V647 Her (M3.5V) obtained at the 1.25-m telescope of the Crimean Astrophysical Observatory in 2022 is presented. The presence of a low-amplitude variability ...
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Article
Open AccessCharacteristics of Long-Term Spot Activity on Several Late-Spectral-Type Stars
We present our analysis of many-year photometry for several dozens of chromospherically active stars that exhibit solar-type activity (from our own observations as well as from data in the literature). Modelin...
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Article
Circumstellar Properties of the Herbig Be Star HD 259431. I. Signatures of Magnetospheric Accretion
Results are presented from a spectroscopic study of the Ae/Be Herbig star HD 259431 conducted from 2010 to 2019 using high-resolution spectrographs at: (a) the Crimean Astrophysical Observatory, (b) European S...
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Article
Analysis of the Spectroscopic Observations of RS CVn Type Star V837 Tau
We present an analysis of the spectra of the star V837 Tau, which belongs to a class of chromosphere-active RSCVn type stars. The observational material was obtained with the 1.5-m Russian-Turkish telescope RT...
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Article
Features of the Wind of the Unique Herbig Ae Star HD 190073
Results of our spectral monitoring of the Herbig Ae star HD190073 during 2009-2017 at the Crimean Astrophysical Observatory are presented. Over this time, 116 spectra were obtained in the region of the Hα line...
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Article
Short-Term Spectral Variability of the Herbig Ae/Be Star HD37806
The spectroscopic variability of the Herbig Ae/Be star HD 37806 is analyzed on temporal scales from night-to-night, and over individual nights. The observations were made during November 2012 on the ASP-14 Cou...
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Article
Long-term Spot-Coverage Variations of 13 BY Dra G–K Dwarfs
The results of spot-coverage modeling for 13 active G–K dwarf stars based on many-year photometric observations are presented. The results of UBVRI observations of eight stars performed at the Crimean Astrophysic...
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Article
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 F...
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Article
Spectral Variability of the Herbig Ae/Be Star HD 37806
Results are reported from a spectroscopic study of the Herbig Ae/Be star HD 37806 from 2009 through 2017 using high resolution spectrographs at the Crimean Astrophysical Observatory and the OAN SPM Observatory...
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Article
Long-Term Spectral Variability of the Spotted Star in Com
High-resolution (R = 20000) spectral observations over many years of the spotted star IN Com in the regions of the Hα, Hβ, and He I 5876 Å lines are reported. The distinctive feature of the spectrum of this st...
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Article
Long-term variations in the spottedness of BY Dra M dwarfs
The results of a spottedness study for twelve red dwarf stars covering several decades and based on a vast amount of photometric observations are presented. The analysis makes use of multicolor (UBV RI) photometr...
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Article
Long-term spottedness variations of 16 RS CVn stars
An improved zonal model for spotted stellar photospheres enabling analysis of two active longitudes simultaneously present on a star is used to determine the spottedness parameters for a sample of chromospheri...
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Article
Three-Component Model of Spottedness in the Classical RS CVn System UX Ari
It is shown that the hypothesis of a complex (cold spots and hot flares) structure for the active regions on UX Ari reproduces well the photometric behavior of the star. According to the model the spots are co...
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Article
Starspots and active regions on IN Com: UBVRI photometry and linear polarization
The activity of the variable star IN Com is considered using the latest multicolor UBVRI photometry and linear polarimetric observations carried out during a decade. The photometric variability of the star is ...
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Article
The stellar wind as a key to the understanding of the spectral activity of IN Com
We present long-term spectral observations (R = 20000) of IN Com in the region of the Hα, Hβ, and He I 5876 lines. One distinguishing characteristic of the stellar spectrum is the presence in the Hα line of an ex...
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Article
Starspots on Young pms Stars
Long-term, multiband photometric observations of 8 young PMS stars are used to construct models for their starspots. It is shown that the average density of starspots is up to 40 % of the total surface of a st...
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Article
Role of molybdenum in increasing the resistance of steel to the breaking effect of hydrogen at elevated temperatures and pressures (hydrogen corrosion)
The physicochemical nature and the mechanism of the breaking effect of hydrogen on steel at elevated temperatures and pressures (hydrogen corrosion) are studied. This phenomenon is found to be based on the che...
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Article
Spot activity of the binary CG Cyg: Observations during maximum spottedness
We present the results of new multicolor photometry of the chromospherically active binary CG Cyg acquired in 2005–2009 (136 hours of observations). The light curves for each season reveal rotational brightnes...
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Article
Topokinetic model of active dissolution of a solid electrode with point lattice defects. analysis and comparison of the results obtained in solving equations with the experimental data
A model that takes into account the consistence between the atomic relief with the metal dissolution (corrosion) rate and also considers the direct effect of point lattice defects (vacancies or atoms of impuri...
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Article
Long-term starspot activity of the eclipsing binaries BH Vir and WY Cnc
We present the results of multicolor photometry of the two spotted, short-period, late-type RS CVn stars BH Vir and WY Cnc. We have derived the parameters of the binaries’ components, and refined their masses,...
