Seven New Variables at the Borderline of Pegasus and Lacerta

M. Mogoryan^#1, N. Virnina^#2, F. Martinelli^#3

#1. Mariinskaya High School, Odessa, Ukraine; #2. Odessa National Maritime University, Odessa, Ukraine; #3. Montecatini Val Di Cecina Astronomical Centre.

Received:   13.11.2013;   accepted:   19.12.2013
(E-mail for contact: maximmogorean@gmail.com, virnina@gmail.com)

Comments:


1. Secondary minimum: HJD = 2456536.8522.
O'Connell effect (O'Connell 1951) is possible. Alternative period is 0^d.5549. Min_II = 13^m.649.

2. Secondary minimum: HJD = 2456534.8598.
Min_II = 17^m.10.

3. Secondary minimum: HJD = 2456535.8633.
Min_II = 15^m.18.

4. Secondary minima:
HJD = 2456534.8861,
HJD = 2456535.8497,
HJD = 2456536.8155.
Min_II = 15^m.13. Variable O'Connell effect is possible. Also there is a flat part on the phase curve in the secondary minimum.

5. Secondary minima:
HJD = 2456159.6101,
HJD = 2456224.3904,
HJD = 2456559.5520.
The phase curve is combined of unfiltered observations, collected in 2012 with Mead 10" (black points); R-filtered observations obtained in 2013 with the same telescope (blue points); and R-filtered observations, made with the T5 telescope of the iTelescope.net observatory (red points).

6. Primary minima:
HJD = 2456535.9370,
HJD = 2456542.7177.
Min_II = 14^m.32. O'Connell effect is clearly present. A total eclipse in the primary minimum is possible. The orbital inclination is close to 90°. Another interesting feature is a rather large difference in minima depths: min_I - min_II = 0^m.28. Despite the shape of the light curve and the period, which are typical of EW-type binaries, the components of this binary do not show thermal contact.

7. Min_II = 14^m.97.

Remarks:
The field centered at RA=22^h48^m, Dec=+34°23′ (2000.0) has been chosen to search for new variable stars: it contained no known variables. The initial unfiltered observations were made at the Montecatini Val Di Cecina Astronomical Centre in Italy using the 10" Mead telescope, equipped with a SBIG KAF 1600 CCD camera, the field of view being 19′×28′.4. We searched for new variables using C-Munipack software and found 3 new variable stars (#2, #4 and #5). Maximum quantum efficiency of the camera turned out to be between the standard Rc and V bands, thus we decided to acquire new filtered observations.

Our R-band observations were collected at the iTelescope.net observatory (USA) with 250‑mm Takahashi Epsilon telescope equipped with an ST-10XME CCD camera. As the field of view of this telescope is wider (40′.4×60′), we have discovered additional 4 variable stars. Thus, altogether we have discovered 7 new variables, which all turned out to be binary stars of different types. The finding charts (10′×10′) are attached.

The comparison stars are:

USNO-B1.0 1242-0521580 (22^h47^m03^s.641; +34°15′31″.29; R = 12^m.238),

USNO-B1.0 1241-0519783 (22^h47^m21^s.808; +34°11′07″.61; R = 13^m.984),

USNO-B1.0 1241-0519638 (22^h46^m49^s.329; +34°10′02″.63; R = 13^m.525);

the star numbers are from the USNO B1.0 catalog (Monet et al. 2003).

The magnitudes of these stars were derived using the SeqPlot program.

To search for the periods of new variables, their initial epochs and extrema we used Peranso software. The periods were determined by the Lafler–Kinman method (Lafler & Kinman 1965).

For each variable star, minima timings were calculated as described by Kwee & van Wörden (1956).

Acknowledgements:

The observations with the T5 telescope of iTelescope.net observatory were possible thanks to their educational and grant programs, conducted by Peter Lake. We are also thankful to Aron Jenkins for technical support.

We also would like to thank Sebastian Otero for helpful discussion and advice about classification of some new variable stars.

Authors are very grateful to the referees for useful comments and advices.

References:
Kwee, K.K., van Wörden, H., A, Bull. Astron. Inst. Ned., 1956, 464, 327
Lafler, J., Kinman, T.D., Astrophys. J. Suppl., 1965, 11, 216
Monet, D.G., Levine, S.E., Canzian, B., et al., 2003, Astron. J., 125, 984
O'Connell, D.J.K., Publ. Riverview Coll. Obs., 1951, 6, 85