Peremennye Zvezdy (Variable Stars) 35, No. 2, 2015
Received 06 March; accepted 12 March.
A Photometric Study of the Double-Mode High-Amplitude Scuti Variable Star QS Draconis
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In this paper, we present the results of our study of QS Draconis, a double-mode high-amplitude Scuti variable star, HADS(B) type. Its coordinates in the GCVS catalog (Samus et al. 2007-2012) are 15213469, +61 29 22 7 (J2000.0).
The variability of QS Dra (GSC 4181-00046) was discovered by one of the autors (Khruslov 2007) from the publicly available data of the Northern Sky Variability Survey (NSVS, Wozniak et al. 2004). The variable was classified as a double-mode high-amplitude Scuti variable star, DSCT(B) type, pulsating in the fundamental and first overtone modes. Khruslov (2007) suggested the following light elements:
(fundamental mode) and
(first overtone mode).
The period ratio is typical of double-mode HADS stars (Petersen & Christensen-Dalsgaard 1996).
In the present paper, we use a much longer series of observations that makes it possible to improve the periods and to detect new interaction frequencies, , , , and .
Reductions were performed using the MaxIm DL aperture photometry package. The finding chart (Fig. 1) identifies the variable star, comparison star, and check star. The comparison star was GSC 4181-00052, 15211604 +61 28 45 2 (J2000.0), and the check star, GSC 4181-00443, 15220416 +61 34 18 8 (J2000.0). The magnitudes of the comparison star are and (Johnson's system) in the AAVSO Photometric All-Sky Survey (APASS, http://www.aavso.org/download-apass-data) catalog. The -band magnitudes could be presented only as magnitude differences with respect to the comparison star.
Our observations are available online in the html version of this paper.
|Mode||Period, d||Epoch, HJD 2456565+|
|Mode||Frequency, c/d||Period, d||Semi-amplitude, mag|
The light curves of QS Draconis in the , and bands are displayed in Figs. 3, 4, 5. Along with the light curves, we present power spectra of QS Draconis, for the raw data and after subtraction of the fundamental-mode oscillations (see Fig. 2).
The star varies within the following range: the -band range is 1271 - 1337; the -band range is from 1263 to 1316. The amplitude in the band is 043 (range from to ).
Figure 6 exhibits light-curve variations from one cycle to another during the same night, typical of high-amplitude double-mode Scuti variables.
Acknowledgments: The authors are grateful to Dr. V. P. Goranskij for providing light-curve analysis software. We wish to thank M. A. Krugov, N. V. Lichkanovsky, I. V. Rudakov, R. I. Kokumbaeva, and W. Mundrzyjewski for their assistance during the observations. This study was supported by the Russian Foundation for Basic Research (grant 13-02-00664), the Programme "Transitional and Outburst Processes in the Universe" of the Presidium of Russian Academy of Sciences, and the program "Studies of Physical Phenomena in Star-forming Regions and Nuclear Zones of Active Galaxies" of the Ministry of Education and Science (Republic of Kazakhstan).
Fig. 3. The light curves of QS Dra, band. Upper panels: raw data; lower panels: the folded light curves with the other oscillation pre-whitened.
Khruslov, A.V., 2007, Perem. Zvezdy Prilozh., 7, No. 25
Petersen, J.O., Christensen-Dalsgaard, J., 1996, Astron. and Astrophys., 312, 463
Samus, N.N., Durlevich, O.V., Kazarovets, E.V., et al., 2007-2012, General Catalogue of Variable Stars, Centre de Donnees Astronomiques de Strasbourg, B/gcvs
Wozniak, P.R., Vestrand, W.T., Akerlof, C.W., et al., 2004, Astron. J., 127, 2436