|#1. Siberian State Aerospace University, Krasnoyarsk, Russia;
#2. Sternberg Astronomical Institute, Lomonosov Moscow State University, Moscow, Russia;
#3. Institute of Astronomy, Russian Academy of Sciences, Moscow, Russia
Received: 23.05.2012; accepted: 12.10.2012
(E-mail for contact: email@example.com)
1. Min II = 15m.31.
4. Min II = 12m.74.
8. Min II = 15m.36.
9. Min II = 13m.70. O′Connell effect.
10. The star in the NSVS database: NSVS ID 5072183, NSVS ID 2724194, NSVS ID 2682439. The NSVS data confirm the star's type and period.
B = 14.6, R = 13.2 (USNO-A2.0). J = 11.995, H = 11.486, K = 11.430 (2MASS).
11. Type EW with the period 0d.55595 is also possible.
12. TSVSC1 TN-N111120113-1-67-2 (Damerdji et al. 2007).
Min II = 13m.11. O′Connell effect.
13. Min II = 14m.94. The period 1d.56575 is also possible.
14. USNO-A2.0 1425-07957319 is located at the distance of r = 13″.4 from the X-ray source 1WGA J1326.3+5432 (HR1 = 0.7308, HR2 = 0.2667), which is larger than the position error of the source (12″). Nevertheless, we believe this is the same object.
The star in the NSVS database: NSVS ID 2679420. The NSVS data confirm the star's type and period.
B = 14.4, R = 13.6 (USNO-A2.0). J = 10.851, H = 10.238, K = 10.071 (2MASS).
15. The star in the NSVS database: NSVS ID 2678698.
B = 14.2, R = 13.4 (USNO-A2.0). J = 11.438, H = 11.018, K = 10.887 (2MASS).
16. J = 12.122, H = 11.481, K = 11.305 (2MASS).
17. TSVSC1 TN-N111120221-1-67-2 (Damerdji et al. 2007).
18. Min II = 14m.56.
19. The star is present in the database of the Catalina Surveys, CSS J134709.1+525920. The Catalina data confirm the star's type and period.
B = 15.5, R = 14.6 (USNO-A2.0). J = 14.056, H = 13.759, K = 13.703 (2MASS).
20. The star is present in the database of the Catalina Surveys, CSS J133920.6+532253. The Catalina data confirm the star's type and period.
An unresolved double star. Min II = 13m.70.
22. The star is present in the database of the Catalina Surveys, CSS J135628.3+542922. The Catalina data confirm the star's type and period.
23. The star is present in the database of the Catalina Surveys, CSS J135340.3+541601. The Catalina data confirm the star's type and period.
In March and April, 2010, we observed four adjacent fields in Ursa Major. Our observations were performed in the observatory of the Siberian State Aerospace University, in the city of Krasnoyarsk, with a Hamilton telescope (D = 400 mm, F = 915 mm), equipped with an FLI ML9000 CCD chip (3056x3056 pixels, pixel size 12 μm). The exposure time was 30 seconds for each frame. The size of the four fields taken together is 9°.2 × 2°.3.
All our CCD observations were obtained without a filter. The magnitudes were referred to red magnitudes of comparison stars from the USNO-A2.0 catalog (Monet et al. 1998).
We used the VaST software (Sokolovsky & Lebedev 2005) to search for new variable stars. We discovered 21 new variable stars and confirmed two stars earlier reported without a variability type. Periods were derived using the WinEfk software provided by V.P. Goranskij. The coordinates in the Table are from the USNO-A2.0 catalog (Monet et al. 1998). Observations for several stars can also be found in the ROTSE-I/NSVS survey (Wozniak et al. 2004) or in the Catalina Surveys (Drake et al. 2009).
Acknowledgements: The authors wish to thank Dr. V.P. Goranskij for his efficient period-search software and Kirill Sokolovsky for providing VaST (a software package for detection of variable objects in a series of astronomical images).
Damerdji, Y., Klotz, A., Boër, M., 2007, Astron. J., 133, 1470
Drake, A.J., Djorgovski, S.G., Mahabal, A., et al., 2009, Astrophys. J., 696, 870
Monet, D., Bird, A., Canzian, B., et al., 1998, USNO-A2.0, A Catalog of Astrometric Standards (U.S. Naval Observatory, Washington, DC), Centre de Donnees Astronomiques de Strasbourg, I/252
Sokolovsky, K., Lebedev, A., 2005, in 12th Young Scientists' Conference on Astronomy and Space Physics, Kyiv, Ukraine, April 1923, 2005, eds.: Simon, A.; Golovin, A., p.79
Wozniak, P.R., Vestrand, W.T., Akerlof, C.W., et al., 2004, Astron. J., 127, 2436