Discovery of 19 new variable stars in the vicinity of the young star cluster King 12. Part I

R. Gaysin^#1, O. Burkhonov^#1,2, R. Karimov^#1, B. Satovskiy^#3, B. Khafizov^#1, S. A. Ehgamberdiev^#1,4, M. Parmanova^#1

#1. Astronomical Institute of the Uzbekistan Academy of Sciences, Tashkent, Uzbekistan; #2. Samarkand State University, Samarkand, Uzbekistan; #3. State Space Corporation "Roscosmos", Moscow, Russia; #4. National University of Uzbekistan, Tashkent, Uzbekistan.

Received:   7.09.2023;   accepted:   1.12.2023
(E-mail for contact: renat@astrin.uz)

Comments:


1. MinII = 16^m.41.

2. MinII = 15^m.55.

3. MinII = 16^m.46.

4. MinII = 15^m.85.

5. MinII = 15^m.64.

6. MinII = 16^m.90.

8. MinII = 18^m.4.

9. MinII = 18^m.40.

10. MinII = 16^m.39.

11. MinII = 17^m.15.

12. MinII = 16^m.15.

14. Our dataset is not long enough to derive light elements for this Algol variable.

17. MinII = 16^m.77.

18. MinII = 16^m.96.

19. MinII = 15^m.71.

Remarks:
We present the results of searching for variable stars in a field in Cassiopea with the center at α=23^h50^m, δ=+61°56' (J2000.0) near the young open star cluster King12. The field of view is 30′. We inspected the available databases containing information on variable stars: GCVS (Samus et al., 2017), VSX, ZTF (Chen et al., 2020) and ASAS-SN Variable Stars Database and found no records for the objects listed in the table. The coordinates were extracted from Gaia DR3 (Gaia Collaboration et al., 2023).

Our observations were carried out at the Maidanak Astronomical Observatory of the Astronomical Institute of the Academy of Sciences of the Republic of Uzbekistan (Ehgamberdiev, 2018) using the 0.5-meter AMT-1 telescope with Mathis Instruments MI-750/1000 equatorial fork mount equipped with an Apogee Alta U16M (2K×2K) CCD camera. The physical size of a CCD pixel is 9 microns. We used 2×2 binning, which corresponds to 0.907′′/pixel, and the field of view of 30.9′×30.9′. The exposure times were 180 seconds in the Bessel R filter. The temperature of the camera was set to 15°C. Calibration images as bias, dark and flat were also obtained for each observational date. The photometric dataset was obtained during the time interval from August 26 to September 4, 2021 (JD 2459453.22–2459462.50). During 10 nights 512 frames were taken. All images were processed with master bias, dark, and flat frames using standard IRAF packages. We rejected low-quality images, and the final sample contained 503 images. The VaST (Variability Search Toolkit) software package (Sokolovsky and Lebedev, 2018) was used to search for variable stars. To derive periods, we used the period search tool by Dr. K.V. Sokolovsky who incorporated it in his VaST package.

Acknowledgments: We are grateful to the staff of the Maidanak Astronomical Observatory for their efforts to support observations.

References:
Chen, X., Wang, S., Deng, L., et al., 2020, Astrophys. J. Suppl. Ser., 249, 18.
Ehgamberdiev, Sh., 2018, Nature Astronomy, 2, 349.
Gaia Collaboration, Creevey, O. L., Sarro, L. M., et al., 2023, Astron. Astrophys., 674, id. A39.
Samus, N. N., Kazarovets, E. V., Durlevich, O. V., Kireeva, N. N., and Pastukhova, E. N., 2017, Astron. Rep., 61, No. 1, 80.
Sokolovsky, K. V. and Lebedev, A. A., 2018, Astron. Computing, 22, 28.