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Article
Study of the Carbon Star T Draconis
We present the results of the infrared photometric observations in the \(JHKLM\) ... bands and infrared spec...
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Article
Recurrent Symbiotic Nova T Coronae Borealis before Outburst
The results of photometric and spectral observations of T CrB obtained in a wide range of wavelengths in 2011–2023 are presented. We use the near-IR light curves to determine a new ephemeris
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Article
FG Sge: New Multicolor Photometry and Short-Term Dust Shell Clearing in 2019
We present the results of a new stage of the long-term photometric study of FG Sge which is a quickly evolving central star of the planetary nebula Hen 1-5. Our new observations carried out on the SAI MSU tele...
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Article
Multicolor Photometry and Peculiarities of the Spectrum for the post-AGB Candidate AU Vulpeculae (IRAS 20160+2734)
We present the results of a UBVRcIc and JHKLM photometric monitoring campaign conducted in 2016–2020, low-resolution spectroscopy, and an analysis of the ASAS-3 and ASAS-SN photometric data for the semiregular...
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Article
Surprising Variability of the Planetary Nebula IC 4997 \(=\) QV Sge
We present the results of a new epoch (2009–2019) of a long-term (50 years) photometric monitoring of the variable planetary nebula IC 4997 (QV Sge). The integral (star + nebula) \(UBV\) light curves display a ...
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Article
A Model of the Dust Envelope of the Carbon Mira Star V CrB from Photometry, Infrared Spectroscopy, and Speckle Polarimetry
\(UBVJHKLM\) photometry for the carbon Mira star V CrB are presented. The infrared observations we...
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Article
Results of Many-year Photometry of the Herbig Ae Star AB Aur in the Near Infrared
The results of many-year infrared observations of the Herbig AeBe star AB Aur at 1-5 μm (JHKLM bands) are presented. The duration of the photometric series, together with observations published earlier, is about ...
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Article
The Relative Wavelength Independence of IR Time Lags in NGC 4151 during the Years 2010–2015
We present results of a study of the correlation between the infrared (JHKL) and optical (B) fluxes of the nucleus of the Seyfert galaxy NGC 4151 for the years 2010–2015 using our own data (partially published) i...
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Article
Cool Spots on the Surface of the Active Giant PZ Mon
Based on the multicolor (BVRIJHKL) photometric observations of the active red giant PZ Mon performed for the first time in the winter season of 2017–2018, we have determined the main characteristics of the spotte...
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Article
Quiescent and Active States of V1413 Aql I: Photometric Activity Criterion and the Detection of a Secondary Minimum
We present the results of our photometric UBV JHKL observations for the symbiotic star V1413 Aql obtained in 2012–2018. An analysis of the data has shown that inMay 2017 the system passed to a quiescent state wit...
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Article
Multicolor Photometry and Spectroscopy of the Yellow Supergiant with Dust Envelope HD 179821 = V1427 Aquilae
We present the results of multicolor (UBV JHKLM) photometry (2009–2017) and low-resolution spectroscopy (2016–2017) of the semi-regular variable V1427 Aql = HD 179821, a yellow supergiant with gas-dust envelope. ...
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Article
X Per and V725 Tau: infrared variations on timescales longer than fifteen years
The results of infrared observations of the two Be stars X Per and V725 Tau, which are the optical components of X-ray binary systems, obtained in 1994–2016 are presented. The observations cover Be-star phases...
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Article
A “tsunami” in the protoplanetary disk of SV Cep
The results of ~15 years of photometric observations of the UX Ori star SV Cep in the near-infrared (JHKL) are presented. They demonstrate the presence of a cyclic component with a period of ~7 years in the varia...
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Article
Photometric and spectroscopic study of the supergiant with an infrared excess V1027 Cygni
We present the results of our UBV and JHKLM photometry for the semiregular pulsating variable V1027 Cyg, a supergiant with an infrared excess, over the period from 1997 to 2015 (UBV) and in 2009–2015 (JHKLM). Tog...
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Article
Photometric activity of UX orionis stars and related objects in the near infrared and optical: CO Ori, RR Tau, UX Ori, and VV Ser
This paper continues a study of the photometric activity of UX Ori stars in the optical and near-infrared (JHKLM bands) initiated in 2000. For comparison, the list of program stars contains two Herbig Ae stars th...
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Article
Symbiotic nova V1016 Cygni: Evolution of the dust envelope and the gaseous nebula
As a result of the next cycle of our long-term monitoring, we present our UBV JHKLM photometry for the symbiotic nova V1016 Cyg in 2008–2014. The star continued to systematically fade and redden in UBV: over this...
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Article
IR photometry and models for the dust shells of two oxygen Mira variables
Long-term JHKLM photometric measurements of the oxygen Mira variables RU Her and RS Vir are presented. Variations of the brightnesses and colors of these stars over the observation period are analyzed, and master...
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Article
Infrared variability of three hot stars on a time scale of 10–20 years
Long-term (1994–2014) near-infrared observations of P Cyg, kDra, and BUTau are analyzed. It is shown that the observed brightness and color variations in P Cyg and k Dra can be explained by variations in the p...
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Article
JHKLM-Observations of the Unique Eclipsing System ε Aur During a Secondary Minimum
Photometric data in the JHKLM near infrared bands obtained in 1999-2000 are presented for the long-period eclipsing system ε Aur. The time of secondary eclipse (when the F21 supergiant eclipses a dust disk sur...
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Article
Correlation of near-infrared and optical variability of NGC 4151 in 2008–2013
We investigate the correlation between infrared (JHKL) and optical (B) fluxes of the variable nucleus of the Seyfert galaxy NGC4151 using partially published data for the last 6 years (2008–2013). We find that th...