Перегляд за Автор "Protsyuk, Yu. I."

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  • Ескіз
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    Data processing of plates containing images of uranus and neptune from ukrvo digital archive: structure, quality analysis
    (Одеський національний університет імені І. І. Мечникова, 2015) Protsyuk, Yu. I.; Yizhakevych, O.; Kovylianska, O. E.; Protsyuk, S.; Andruk, V. N.; Kashuba, S.; Kazantseva, L. V.
    To use accumulated resources of UkrVO digital archive, analysis of the available photographic plates containing images of Uranus and Neptune was conducted. Data processing of selected plates was also caried out to provide an estimate of positional precision and accuracy. Archives of the Research Institute: Nikolaev Astronomical Observatory (NAO), Main Astronomical Observatory of National Academy of Science (MAO), Astronomical Observatory of Odessa National University (AO ONU), Astronomical Observatory of Kyiv National University (AO KNU) were used. Numbers of plates containing images of Uranus and Neptune are, respectively, the following: 220 and 218 plates in NAO, 64 and 35 plates in MAO, 54 and 44 plates in AO ONU, 3 and 1 in AO KNU. Plates of NAO and MAO have 2 or 3 exposures per plate, and other plates have only one exposure per plate. The epoch of observation for most plates is 1960 to 1998, and for only one plate is 1908. All plates were scanned with the resolution not less than 1200 dpi. Each plate of NAO was scanned 5 to 6 times. Plates containing images of Uranus and Neptune were, respectively, scanned 618 and 952 times in NAO. All plates of other observatories were scanned only once. Raw image processing for scans containing images of Uranus and Neptune was conducted for all scans obtained in observatories. (X, Y) coordinates, (I) intensities and FWHM values were obtained for images of all objects. Star identification for scans containing images of Uranus and Neptune was, respectively, conducted for 600 and 936 scans in NAO and for 71 scans in MAO. Coordinates of all objects were obtained. Positional accuracy of reference stars was estimated for 244 plates of NAO and 66 plates of MAO, and has value of 0.08″-0.26″.
  • Ескіз
    Документ
    Method for evaluating the astrometric and photometric characteristics of commercial scanners in their application for the scientific purpose
    (Astroprint, 2014) Protsyuk, Yu. I.; Andruk, V. N.; Muminov, M. M.; Yuldoshev, Q. X.; Ehgamberdiev, Sh. A.; Eglitis, I.; Eglite, M.; Kovylianska, O. E.; Golovnya, V. V.; Kazantseva, L. V.; Kashuba, S. G.
    Method for estimating the accuracy of astrometric (rectangular coordinates) and photometric (diameters and magnitudes) characteristics of commercial scanners is proposed and applied. The method is demonstrated using an example of processing of sequential scans of plates, which were exposed with different telescopes and then digitized with resolution of 1200 dpi with several Epson scanners. Scanning operations were carried out in various observatories as part of development of the database of photographic observations for Virtual Observatories (Vavilova, 2012). Errors of studied scanners are equal to σx, y = ± 0.02-0.06px and σm = ± 0.015-0.024 mag for astrometry and photometry, respectively.
  • Ескіз
    Документ
    Spectroscopic investigations of Galactic clusters with associated cepheid variables II NGC 5662 and V CEN
    (Одеський національний університет імені І. І. Мечникова, 2018) Usenko, I. A.; Kniazev, A. Yu.; Kovtyukh, Valery V.; Mishenina, T. V.; Miroshnichenko, A. S.; Turner, D. G.; Protsyuk, Yu. I.
    We present the results of a spectroscopic and photometric investigation of 15 objects from the open cluster NGC 5662, which contains the Cepheid V Cen. Besides the Cepheid, we studied one G-supergiant, two K-giants, four B-giants, and seven main sequence stars. Radial velocities (RV), vsini, TeS, logg, and [Fe/Hj were determined using model fitting. We have derived the color-excesses, reddenings, and intrinsic colors for these stars to determine their true Tff and log g from comparison to the atmosphere models, especially for hot stars, and to determine their absolute magnitudes. RV and GAIA DR2 2018 parallax/distanee values for these stars allowed us to determine their membership in the cluster and to construct it 3D kinematic models. These parallaxes and reddenings led to the distances in a range of 700875 pc, while photometric My gave the distances of 550-660 pc. Two objects from our list were found to be non-members of the cluster, and two other objects to be background stars. All members have [Fe/Hj = —0.1 ±0.04 dex. The main sequence stars and B-giants have abundances of C, N, and Na close to the solar one, while the cool supergiants and giants show a deficit of carbon, an overabundance of nitrogen, and a small overabundance or close to the solar sodium content. Two Li-rich K-giants, HD 127733 and HD 127753, were discovered in the cluster.
  • Ескіз
    Документ
    Spectroscopic investigations of Galactic clusters with associated cepheid variables. I. Polaris cluster and UMi
    (Одеський національний університет імені І. І. Мечникова, 2018) Usenko, I. A.; Miroshnichenko, A. S.; Danford, S.; Kovtyukh, Valery V.; Turner, D. G.; Shulga, O. V.; Protsyuk, Yu. I.
    We present the results of an analysis of the spectra of nine so called Polaris cluster A􀀀FV stars obtained during 2016-2018. Radial velocities (RV) and GAIA DR 18 parallaxes-distances for these stars allow us to determine their membership in the cluster and to construct its 3D kinematic model. However Teff for four stars determined spectroscopically give cause for doubts about the GAIA DR 18 parallaxes accuracy. The comparison between their MV and distances with the those from Pecaut & Mamajek (2013) calibrations shows signi cant di erences for the objects with parallaxes less than 8 mas. The di erences in distances increase exponentially with decreasing parallax. These facts indicate an unreliability of the GAIA DR2 parallx measurements of less than 10 mas. We estimated the distance to Polaris B to be 104.2 pc.