New Variable Stars in Ophiuchus III

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

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

Received:   20.08.2012;   accepted:   22.11.2012
(E-mail for contact: bredfild@mail.ru, sav@surgut.ru, bs25@mail.ru)

Comments:


1. Minimum: HJD(TT) 2455720.3404±0.0009.

2. Infrared colors J–H = 0.591, H–K = 0.159, J–K = 0.750 (2MASS) are consistent with the K spectral type (Bessell and Brett 1988) and BY: classification.

3. O'Connell effect. Primary minima:

HJD(TT)	±
2455649.5475	0.0004
2455723.2995	0.0006

Min_II=15^m.33.

4. Infrared colors J–H = 0.544, H–K = 0.272, J–K = 0.816 (2MASS) are consistent with the K or M spectral type (Bessell and Brett 1988) and BY: classification.

5. O'Connell effect. Min_II=15^m.06.

6. Infrared colors J–H = 0.676, H–K = 0.108, J–K = 0.784 (2MASS) are consistent with the K spectral type (Bessell and Brett 1988) and BY: classification.

7. Primary minima:

HJD(TT)	±
2455676.432	0.001
2455679.424	0.001

Min_II=18^m.37.

8. Min_II=13^m.61.

Remarks:
During observations of a field in Ophiuchus, we discovered eight new variable stars. Our observations were carried out at the Astrotel-Caucasus observatory, located at the Astronomical station of the Kazan Federal university, using the 300-mm Ritchey-Chretien telescope, equipped with an unfiltered Apogee Alta U9000 CCD camera. A total of 326 images with 5-minute exposures were obtained on JD 2455632–2455749. For basic reductions for dark current, flat fields and bias we used IRAF routines. For search and photometry of new variable stars, we applied VaST software by Sokolovsky and Lebedev (2005). The comparison star was USNO-A2.0 0975-08679115 = USNO-B1.0 1020-0315967 (α=16^h56^m12^s.11, δ=+12°04′ 04″.5 (J2000, 2MASS)), R₁=14^m.63, R₂=14^m.78 (USNO-B1.0). Unfiltered magnitudes were calibrated using the comparison star, assuming R_comp=14^m.705. The coordinates of the variable stars in the table were drawn from the 2MASS catalogue (Skrutskie et al. 2006). For search for periods and epochs of extrema, we use Peranso software (www.peranso.com).

References:
Bessell, M.S., Brett, J.M., 1988, Publ. of Astron. Society of Pacific, 100, 1134
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