New Variable Stars in Aquila II

T. Kryachko^#1, A. Samokhvalov^#2, B. Satovskiy^#1

#1. Astrotel Observatory, Karachay-Cherkessia, Russia; #2. Surgut, Russia

Received:   28.08.2012;   accepted:   13.12.2012
(E-mail for contact: bredfild@mail.ru, sav@surgut.ru, bs25@mail.ru)

Comments:


1. Maximum: HJD(TT) 2455796.263 ± 0.001.

2. A close pair of USNO-A2.0-0900-17238865 and a faint star, not present in any of major catalogues. USNO-A2.0-0900-17238865 varies. Primary minimum: HJD(TT) 2455679.5163 ± 0.0003. Min_II = 17^m.63.

3. A close pair of two stars, not present separately in any major catalogues. Type RRC with period 0^d.24967 or type EW with periods 0^d.66579 or 0^d.49934 are not excluded. Min_II = 15^m.62.

4. Possible Blazhko effect.

5. Min_II = 18^m.25.

6. Infrared colors J–H = 0.654, H–K = 0.132, J–K = 0.786 (2MASS) are consistent with the K spectral type (Bessell and Brett 1988) and BY: classification.

7. Min_II = 19^m.7.

8. Infrared colors J–H = 0.986, H–K = 0.345, J–K = 1.331 (2MASS) are consistent with the M spectral type (Bessell and Brett 1988) and SR classification. Maximum: HJD(TT) 2455720.

9. A close triplet of stars: 2MASS 19582642+0501114, 2MASS 19582645+0501154 and 2MASS 19582662+0501104. The angular resolution of our telescope is insufficient to determine which star varies. Min_II = 15^m.02.

10. Min_II = 15^m.23.

11. Maximum: HJD(TT) 2455756.4052 ± 0.0001.

12. A close pair of two stars, not present separately in any major catalogues. Min_II = 14^m.90.

13. Min_II = 17^m.70.

14. Min_II = 18^m.24.

15. Infrared colors J–H = 0.564, H–K = 0.141, J–K = 0.705 (2MASS) are consistent with the K spectral type (Bessell and Brett 1988) and BY: classification.

16. Infrared colors J–H = 0.707, H–K = 0.168, J–K = 0.875 (2MASS) are consistent with the M spectral type (Bessell and Brett 1988) and SR classification. Maximum: HJD(TT) 2455734.8 ± 0.2.

17. Infrared colors J–H = 0.893, H–K = 0.263, J–K = 1.156 (2MASS) are consistent with the M spectral type (Bessell and Brett 1988) and SR: classification. Type LB is also possible.

18. Min_II = 16^m.99.

19. Min_II = 15^m.00.

20. Infrared colors J–H = 0.864, H–K = 0.282, J–K = 1.146 (2MASS) are consistent with the M spectral type (Bessell and Brett 1988) and LB classification.

21. O'Connell effect. Min_II = 17^m.94.

22. Infrared colors J–H = 0.539, H–K = 0.119, J–K = 0.658 (2MASS) are consistent with the K spectral type (Bessell and Brett 1988) and BY: classification.

23. Primary minimum: HJD(TT) 2455677.5226 ± 0.0008. Min_II = 17^m.58.

24. O'Connell effect. Min_II = 16^m.28.

25. Min_II = 18^m.93.

26. The one-day alias period 0^d.058916 is also possible. Maximum: HJD(TT) 2455676.5387 ± 0.0008.

27. Period 0^d.30306 is also possible. Min_II = 17^m.20.

28. A close pair of 2MASS 20002353+0505174 and 2MASS 20002364+0505211. 2MASS 20002353+0505174 varies.

29. Infrared colors J–H = 0.596, H–K = 0.129, J–K = 0.725 (2MASS) are consistent with the K spectral type (Bessell and Brett 1988) and BY: classification. At the phase 0.91, we detect an eclipse-like minimum.

30. Period 0^d.42243 is also possible. Min_II = 17^m.10.

31. Blazhko effect.

32. Infrared colors J–H = 0.949, H–K = 0.404, J–K = 1.353 (2MASS) are consistent with the M spectral type (Bessell and Brett 1988) and SR classification.

33. The one-day alias period 0^d.109205 is also possible.

34. Min_II = 15^m.79.

35. Maximum: HJD(TT) 2455737.1.

Remarks:
During observations of a field in Aquila, we discovered 35 new variable stars. Our observations were carried out at the Astrotel-Caucasus observatory, located at the Astronomical station of the Kazan Federal university (Northern Caucasus), using the 300-mm Ritchey-Chretien telescope, equipped with an unfiltered Apogee Alta U9000 CCD camera. A total of 203 images with 5-minute exposures were obtained on JD 2455676–2455832. For basic reductions for dark current, flat fields and bias, we used IRAF routines. To search for of new variable stars and perform their photometry, we applied VaST software by Sokolovsky and Lebedev (2005). The comparison star was USNO-A2.0 0900-17301510 = USNO-B1.0 0948-0507157 (α = 19^h59^m01^s.81, δ = +04°48′ 20″.5 (J2000, 2MASS)), R₁ = 14^m.30, R₂ = 14^m.60 (USNO-B1.0). Unfiltered magnitudes were calibrated using the comparison star, assuming R_comp = 14^m.45. The coordinates of the variable stars in the table were drawn from the 2MASS catalogue (Skrutskie et al. 2006) except for stars: USNO-A2.0 0900-17262085, USNO-A2.0 0900-17267377, and USNO-A2.0 0900-17363874; their coordinates were drawn from the USNO-A2.0 catalogue (Monet et al. 1998). We searched for periods and epochs of extrema using Peranso software.

Acknowledgements: We would like to thank S.V. Antipin for helpful discussion.

References:
Bessell, M.S., Brett, J.M., 1988, Publ. Astron. Soc. Pacific, 100, 1134
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
Skrutskie, M.F., Cutri, R.M., Stiening, R., et al., 2006, Astron. J., 131, 1163
Sokolovsky, K., Lebedev, A., 2005, in 12th Young Scientists' Conference on Astronomy and Space Physics, Kyiv, Ukraine, April 19-23, 2005, eds.: Simon, A.; Golovin, A., p.79