Comments:
1. According to VSX, variability of GSC 0839-00170
was reported in 2013 by Alexandr Ditkovsky (VS-COMPAS project), based on ROTSE-I/NSVS
data.
VSX suggests type RRC with Blazhko effect, the listed light elements are: HJD(max)
= 2453362.802 + 0.417517×E.
Based on the data from ROTSE-I/NSVS, ASAS-3 and Catalina Surveys, it is actually
a double-mode RR Lyrae star, type RR(B),
with the light elements tabulated below.
| Mode |
Frequency, c/d |
Semi-amplitude, mag |
Period, days |
Epoch, JD |
| f1 |
2.395101 |
0.150 (CV, CSS, MLS), 0.172 (V, ASAS), 0.097 (R, NSVS) |
0.417519 |
2455000.747 |
| f0 |
1.785472 |
0.080 (CV, CSS, MLS), 0.081 (V, ASAS), 0.061 (R, NSVS) |
0.560076 |
2455000.521 |
| f1 + f0 |
4.180515 |
0.040 (CV, CSS, MLS) |
0.239205 |
2455000.638 |
| f1 – f0 |
0.609611 |
0.021 (CV, CSS, MLS) |
1.64039 |
2455001.24 |
The period ratio of the first-overtone and fundamental modes is P1/P0
= 0.7455.
J–K = 0.234 (2MASS), B–V = 0.344 (APASS).
Combined brightness of two stars, GSC 0839-00170 (= var) and GSC 0839-00205, was
measured in NSVS, the amplitudes are somewhat underestimated.
2. Variability of USNO-A2.0 0900-06813517 was discovered by Alexandr Ditkovsky from
VS-COMPAS project in 2012, based on ROTSE-I/NSVS data.
The AAVSO Variable Star Index suggests type RRC with Blazhko effect, the listed light
elements are: HJD(max) = 2452732.721 + 0.348758×E.
Based on data from Catalina Surveys, it is actually a double-mode RR Lyrae star,
type RR(B),
with the light elements tabulated below.
| Mode |
Frequency, c/d |
Semi-amplitude, CV mag |
Period, days |
Epoch, JD |
| f1 |
2.867342 |
0.169 |
0.348755 |
2455000.680 |
| f0 |
2.130992 |
0.092 |
0.469265 |
2455000.701 |
| f1 + f0 |
4.998276 |
0.037 |
0.200069 |
2455000.673 |
The period ratio of the first-overtone and fundamental modes is P1/P0
= 0.7432.
J–K = 0.238 (2MASS), B–V = 0.265 (APASS).
The ROTSE data with photometric correction flags were kept for the analysis.
3. The variability of USNO-A2.0 0750-08069398 was reported by Keller et al. (2008;
Id. 109253.24).
The variable was classified as an RR: star without light elements.
Based on Catalina Surveys data, it is actually a double-mode RR Lyrae star, type
RR(B), with the light elements tabulated below.
| Mode |
Frequency, c/d |
Semi-amplitude, CV mag |
Period, days |
Epoch, JD |
| f1 |
2.866159 |
0.144 |
0.348899 |
2454800.775 |
| f0 |
2.130456 |
0.121 |
0.469383 |
2454800.730 |
The period ratio of the first-overtone and fundamental modes is P1/P0
= 0.7433. J–H = 0.280 (2MASS).
4. The variability of V1360 Cen was discovered by Hoffmeister (1963).
The variable is listed in the GCVS (Samus et al. 2007–2013)
as an RR Lyrae star, type RRC, with the light elements: JD(max) = 2452498.53 + 0.344249×E.
Based data from 1SWASP, ASAS-3 and Catalina Surveys, it is actually a double-mode
RR Lyrae star, type RR(B),
with the light elements tabulated below.
| Mode |
Frequency, c/d |
Semi-amplitude, mag |
Period, days |
Epoch, JD |
| f1 |
2.904798 |
0.164 (CV, SSS), 0.200 (WASP), 0.194 (V, ASAS) |
0.344258 |
2454200.540 |
| f0 |
2.159491 |
0.100 (CV, SSS), 0.132 (WASP), 0.115 (V, ASAS) |
0.463072 |
2454200.806 |
| f1 + f0 |
5.06429 |
0.045 (CV, SSS), 0.055 (WASP), 0.048 (V, ASAS) |
0.197461 |
2454200.623 |
| f1 – f0 |
0.745323 |
0.028 (CV, SSS), 0.031 (WASP) |
1.34170 |
2454200.90 |
| 2f1 + f0 |
7.96902 |
0.019 (WASP) |
0.125486 |
2454200.579 |
The period ratio of the first-overtone and fundamental modes is P1/P0
= 0.7434.
J–K = 0.200 (2MASS); B–V = 0.355 (APASS).
When plotting the phased light curves for the identified frequencies, f1
and f0,
we also subtracted variations
of the mean brightness in the 1SWASP data, probably of instrumental origin
(corresponding to the frequency f = 1 in the power spectra).
All the observations from the SuperWASP with the error >
0.m05 were rejected.
5. Variability of GSC 0925-00503 was discovered by Alexandr Ditkovsky from VS-COMPAS
project in 2012, based on ROTSE-I/NSVS data.
The AAVSO Variable Star Index suggests type RRC with Blazhko effect, the listed light
elements are: HJD(max) =
2454663.561 + 0.41189×E.
Based on the data from ROTSE-I/NSVS, ASAS-3 and Catalina Surveys, it is actually
a double-mode RR Lyrae star, type RR(B),
with the light elements tabulated below.
| Mode |
Frequency, c/d |
Semi-amplitude, mag |
Period, days |
Epoch, JD |
| f1 |
2.427833 |
0.150 (CV, CSS), 0.208 (V, ASAS), 0.123 (R, NSVS) |
0.411890 |
2455000.885 |
| f0 |
1.810391 |
0.086 (CV, CSS), 0.116 (V, ASAS), 0.056 (R, NSVS) |
0.552367 |
2455000.520 |
| f1 + f0 |
4.23824 |
0.041 (CV, CSS) |
0.235947 |
2455000.702 |
| f1 – f0 |
0.617452 |
0.035 (CV, CSS) |
1.61956 |
2455000.74 |
The period ratio of the first-overtone and fundamental modes is P1/P0
= 0.7457.
J–K = 0.214 (2MASS); B–V = 0.217 (APASS).
Combined brightness of two stars,
GSC 0925-00503=var and GSC 0925-00363, was measured in the NSVS,
the tabulated amplitudes are somewhat underestimated.
6. The variability of USNO-A2.0 0675-14795162 was reported by Keller et al. (2008;
Id. 111137.2696).
The variable was classified as an RR: star without light elements.
Based on Catalina Surveys data, it is actually a double-mode RR Lyrae star, type
RR(B), with the light elements tabulated below.
| Mode |
Frequency, c/d |
Semi-amplitude, SV mag |
Period, days |
Epoch, JD |
| f1 |
2.779415 |
0.163 |
0.359788 |
2454800.660 |
| f0 |
2.069806 |
0.104 |
0.483137 |
2454800.795 |
The period ratio of the first-overtone and fundamental modes is P1/P0
= 0.7447.
J–K = 0.391 , J–H = 0.388 (2MASS).
7. The variability of USNO-A2.0 0975-20240597 was discovered in 2013 by
Igor Baluk, Sergei Dubrovski and Alexander Pobiyaha from Astrobloknot Team,
based on CSS data. The light elements were given as: HJD(max) = 2455999.857 + 0.353608×E;
the star shows Blazhko effect.
Based on data from Catalina Surveys, it is actually a double-mode RR Lyrae star,
type RR(B),
with the light elements tabulated below.
| Mode |
Frequency, c/d |
Semi-amplitude, SV mag |
Period, days |
Epoch, JD |
| f1 |
2.827942 |
0.165 |
0.353614 |
2455000.555 |
| f0 |
2.104448 |
0.059 |
0.475184 |
2455000.685 |
| f1 + f0 |
4.93247 |
0.039 |
0.202738 |
2455000.594 |
The period ratio of the first-overtone and fundamental modes is P1/P0
= 0.7442.
J–K = 0.288 (2MASS), B–V=0.15 (APASS).
Remarks:
We present a new investigation of seven known RR Lyrae variable stars.
We analyzed all observations available for these stars
in the
Catalina Surveys (Drake et al. 2009), Northern Sky Variability Survey (NSVS , Woźniak et al.
2004),
ASAS-3 (Pojmanski 2002)
and
SuperWASP (Butters et al. 2010)
online public archives using
the period-search software developed by Dr. V.P. Goranskij for Windows
environment.
According to these data, the variables are double-mode RR Lyrae variables,
pulsating
in the first-overtone and
fundamental modes.
Their period ratios, P1 / P0, are typical of radially
pulsating
double-mode RR Lyrae stars.
Along with the light curves, we present power spectra of the RR Lyrae 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 SuperWASP observations are available as FITS tables, which were converted
into ASCII tables using the OMC2ASCII program as
described by Sokolovsky (2007).
The tabulated coordinates of the variables were drawn either from the UCAC4,
2MASS
catalogs or from the GCVS (Samus et al. 2007–2013).
Acknowledgements: Thanks are due to Dr. K.V. Sokolovsky for his advice
concerning
data retrieving.
The authors wish to thank Dr. V.P. Goranskij for providing his software.
This study was supported by the Russian Foundation for Basic Research (grant 13-
02-00664)
and by the Programme "Non-stationary Phenomena of Objects in the Universe" of
the
Presidium of Russian Academy of Sciences.
References:
Butters, O.W., West, R.G., Anderson, D.R., et al., 2010, Astron. Astrophys.,
520,
L10
Drake, A.J., Djorgovski, S.G., Mahabal, A., et al., 2009, Astrophys. J., 696,
870
Hoffmeister, C., 1963, Veröff. Sternwarte Sonneberg, 6, 1
Keller, S.C., Murphy, S., Prior, S., et al., 2008, Astrophys. J., 678, 851
Pojmanski, G., 2002, Acta Astron., 52, 397
Samus, N.N., Goranskij V.P., Durlevich O.V., Kazarovets E. V., Kireeva N.N.,
Pastukhova E.N., Zharova A.V., 2007–2013, General
Catalogue
of Variable Stars, Centre de Donnees Astronomiques de Strasbourg, B/gcvs
Sokolovsky, K.V., 2007, Perem. Zvezdy Prilozh., 7, No. 30
Woźniak, P.R., Vestrand, W.T., Akerlof, C.W., et al., 2004, Astron. J.,
127,
2436
