|#1. Institute of Astronomy, Russian Academy of Sciences, Moscow, Russia;
#2. Bundesdeutsche Arbeitsgemeinschaft fuer Veraenderliche Sterne e.V. (BAV), Berlin, Germany;
#3. Braubach, Germany;
#4. Linz, Austria.
Received: 26.03.2013; accepted: 11.09.2013
(E-mail for contact: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org)
1. The variability of V722 Cen was discovered by Hoffmeister (1963, S 6555). The variable is listed in the GCVS as an RR star without light elements. V0722 Cen has been identified as a double-mode RR Lyrae star, type RR(B), by analysis of Catalina Real-Time Transient Survey (CRTS) data (Drake et al. 2009). The light elements are:
Mode Frequency, c/d Semi-amplitude, ÑV mag Period, days Epoch, JD f0 2.180450 0.177 0.458621 2454800.818 f1 2.936564 0.153 0.340534 2454800.828 f1 + f0 5.117037 0.053 0.1954256 2454800.609 f1–f0 0.756184 0.044 1.32243 2454800.76
The period ratio is P1 / P0 = 0.7425. J–K = 0.634 (2MASS), B–V = 0.298 (The AAVSO Photometric All-Sky Survey, hereafter APASS).
2. The variability of NSV 7160 = GSC 6189–01386 was discovered by Hanley (1942, HV 10687). The star is classified as an RR Lyrae star ("Cluster"). The variable is listed in the GCVS as an RR star without light elements. Drake et al. (2013) give type RRAB with the following elements: HJD 2453553.3923 + 0.844092×E. We re-analyzed Catalina Sky Survey (CSS) and Siding Springs Survey (SSS) data (Drake et al. 2009), this period is wrong, the variable is actually a double-mode RR Lyrae star of RR(B) type. The light elements are:
Mode Frequency, c/d Semi-amplitude, ÑV mag Period, days Epoch, JD f1 2.32223 0.150 0.43062 2455000.647 f0 1.72840 0.035 0.57857 2455000.800
The period ratio is P1 / P0 = 0.7443. J–K = 0.306 (2MASS), B–V = 0.426 (APASS).
3. The variability of GSC 5195–00550 was reported by Süveges et al. (2012, Id. 2345453). They classified the variable as a High-Amplitude Delta Scuti star (HADS) with the period 0.080586 days. According to the CSS data (Drake et al. 2009), it is a double-mode HADS star. The light elements are:
Mode Frequency, c/d Semi-amplitude, ÑV mag Period, days Epoch, HJD f0 12.40910 0.130 0.0805860 2454700.5735 f1 16.01591 0.027 0.0624379 2454700.5607 f1–f0 3.606780 0.021 0.2772556 2454700.523 f1 + f0 28.42508 0.014 0.0351802 2454700.530
The period ratio is P1 / P0 = 0.7748. J–K = 0.142 (2MASS), B–V = 0.528 (APASS).
4. The variability of AG Aqr was discovered by Hughes (1931, HV 4965), The star is classified as a short-period variable. It is listed in the GCVS as an RR: star without light elements, with a reference to Bond (1978). According to the SSS data (Drake et al. 2009), it is a double-mode High-Amplitude Delta Scuti star, type HADS(B). The light elements are:
Mode Frequency, c/d Semi-amplitude, ÑV mag Period, days Epoch, JD f0 3.427745 0.098 0.291737 2454800.650 f1 4.50041 0.040 0.222202 2454800.606
The period ratio is P1 / P0 = 0.7617. The period is unusually long period for this type. J–K = 0.237 (2MASS). B–V = 0.233 (APASS).
We present a new investigation of four variable stars. We analyzed all observations available for these stars in the Catalina Surveys (Drake et al. 2009) online public archives using the period-search software developed by Dr. V.P. Goranskij for Windows environment and Period04 code (Lenz and Breger 2005). According to these data, the variables are double-mode variables (RR Lyrae and High-Amplitude Delta Scuti stars), pulsating in the first-overtone and fundamental modes.
Their period ratios, P1 / P0, are typical of radially pulsating double-mode RR Lyrae and HADS stars. Along with the light curves, we present power spectra of the variables, for the raw data and after subtraction of the first-overtone oscillations. The structure of the power spectra shows that the secondary periods are real.
The tabulated coordinates of the variables were drawn either from the 2MASS catalog (Skrutskie et al. 2006) or from the GCVS (Samus et al. 2007–2012).
Acknowledgements: The authors wish to thank Dr. V.P. Goranskij for providing his software.
The CSS survey is funded by the National Aeronautics and Space Administration under Grant No. NNG05GF22G issued through the Science Mission Directorate Near-Earth Objects Observations Program. The CRTS survey is supported by the U.S.~National Science Foundation under grants AST-0909182.
Bond, H.E., 1978, PASP, 90, 526
Drake, A. J., Catelan, M., Djorgovski, S. G., et al., 2013, Astrophys. J., 763, 20
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Hanley, C.M., 1942, Harvard Observ. Annals, 109, 15
Hoffmeister, C., 1963, Veröff. Sternwarte Sonn., 6, 1
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Lenz, P., Breger, M., 2005, Comm. in Asteroseismology, 146, 53
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
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Süveges, M., Sesar, B., Váradi, M., 2012, Monthly Not. Roy. Astron. Soc., 424, 2528