Comments:
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, SV 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, SV 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, SV 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, SV 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).
Remarks:
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.
References:
Bond, H.E., 1978, PASP, 90, 526
Drake, A. J., Catelan, M., Djorgovski, S. G., et al., 2013, Astrophys. J., 763,
20
Drake, A.J., Djorgovski, S.G., Mahabal, A., et al., 2009, Astrophys. J., 696,
870
Hanley, C.M., 1942, Harvard Observ. Annals, 109, 15
Hoffmeister, C., 1963, Veröff. Sternwarte Sonn., 6, 1
Hughes, E.M., 1931, Harvard Observ. Bull., 883, 18
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
Skrutskie, M.F., Cutri, R.M., Stiening, R., et al., 2006, Astron. J., 131, 1163
Süveges, M., Sesar, B., Váradi, M., 2012, Monthly Not. Roy. Astron.
Soc.,
424, 2528
