PERIOD VARIATIONS IN THE CLOSE BINARY BM UMa

Автор(и)

  • N. A. Virnina Department ”High and Applied Mathematics”, Odessa National Maritime University, Odessa, Ukraine, Ukraine
  • E. A. Panko Astronomical observatory, Odessa National University, Odessa, Ukraine; Astronomical Observatory, Nikolaev National University, Nikolaev, Ukraine; Visiting Astronomer, Department of Astronomy, Saint Mary’s University, Halifax, Nova Scotia, Canada, Ukraine
  • O. G. Sergienko Astronomical Observatory, Nikolaev National University, Nikolaev, Ukraine, Ukraine
  • B. A. Murnikov Astronomical observatory, Odessa National University, Odessa, Ukraine, Ukraine
  • E. G. Gubin Astronomical observatory, Odessa National University, Odessa, Ukraine, Ukraine
  • A. V. Klabukova Astronomical observatory, Odessa National University, Odessa, Ukraine, Ukraine
  • A. I. Movchan Astronomical observatory, Odessa National University, Odessa, Ukraine, Ukraine

DOI:

https://doi.org/10.18524/1810-4215.2010.23.85256

Ключові слова:

Stars, eclipsing variables, period variations, stars, individual, BM UMa.

Анотація

We present the results of analysing of the light curve and O–C variations in the eclipsing system BM UMa, based on V-band observations which cover the period from JD 2454933 to 2454961 using two robotic remotely-controlled telescopes of Tzec Maun Observatory (USA) along with observations made with the RK-600 telescope of Odessa Astronomical Observatory. The full light curve displays a total primary eclipse with a duration 0.06 of the period, or 24 minutes, and a partial secondary eclipse, with both maxima of equal magnitude. For our obesrvations, we determined the statistically optimal values of the initial epoch of T0 = 2454944.2814 ± 0.0001 and orbital period of P = 0.d271226± 0.000002. The depths of primary and secondary minima are nearly equal, 0.m838 ± 0.006 and 0.m748 ± 0.006, respectively. The physical parameters of the system were calculated using the Wilson-Devinney code, appended with the Monte Carlo search algorithm. The result establishes BM UMa as a contact system (fillout factor 10.7%) with parameters: mass ratio 0.538 ± 0.001, inclination 86.°815 ± 0.005, and temperatures of components 4700 ± 20 K and 4510 ± 10 K. The more massive component is larger and cooler. The 72 archival and 11 newly-obtained times of light minimum cover the interval 1961-2010 and allowed us to exclude possible systematic period variations in BM UMa and to determine an initial epoch of HJD 2447927.382 and orbital period of P = 0.d2712209± 0.0000006.

Посилання

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Опубліковано

2010-12-02

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