Comments:
1. The variability
of GSC 3282-00145 was discovered in 2013 by Alexandr Ditkovsky (the
VS-COMPAS project) from ROTSE-I/NSVS data.
The AAVSO Variable Star Index suggests type RRC,
with the light elements:
Max = HJD 2451541.127 + 0d.204929 × E.
According to data from 1SWASP (Butters et al. 2010), it is actually an RRC star
with a non-radial pulsation co-existing with the first-overtone mode. The light elements
are:
| Mode |
Frequency, c/d |
Semi-amplitude, WASP_mag |
Period, days |
Epoch, HJD |
| f1 |
4.87971 |
0.124 |
0.204930 |
2454380.119 |
| f2 |
5.32586 |
0.030 |
0.187763 |
2454380.080 |
The period ratio is P2 / P1 = 0.9162.
J–K = 0.206 (2MASS).
2. The variability of GSC 1340-00246 was discovered by Pojmanski (2002).
The ASAS-3 catalog lists the variable as a DSCT star with the elements:
Max = HJD 2452622.986 + 0d.094964 × E.
I re-investigated the star using the currently available ASAS-3 and 1SWASP data.
It is actually a HADS(B) star, pulsating in the fundamental and
first overtone modes.
The light elements are:
| Mode |
Frequency, c/d |
Semi-amplitude,
WASP mag / V(ASAS) mag |
Period, days |
Epoch, HJD |
| f1 |
8.524640 |
0.089 / 0.114 |
0.1173070 |
2454000.099 |
| f0 |
6.551002 |
0.066 / 0.093 |
0.1526484 |
2454000.133 |
| f1 + f0 |
15.07563 |
0.026 / 0.037 |
0.0663322 |
2454000.0398 |
| f1 – f0 |
1.97348 |
0.015 / – |
0.50672 |
2454000.47 |
| 2f1 |
17.04931 |
0.008 / – |
0.0586534 |
2454000.0328 |
| 2f1 + f0 |
23.60038 |
0.006 / – |
0.0423722 |
2454000.0215 |
The period ratio is P1 / P0 = 0.7685;
possibly P2 / P1 = 0.7870 and
P2 / P0 = 0.6048.
J–K = 0.166 (2MASS).
From the ASAS-3 data, the variability range is 12m.12 – 12m.74
in the V band.
3. The variability of OGLE-BLG-RRLYR-00293 was discovered by Soszynski et al.
(2011a).
The variable was classified as an RRAB variable with the light elements:
Max = HJD 2455000.13654 + 0d.42303636 × E.
I re-analyzed the OGLE-III observations. Actually, this is a double-mode Cepheid
(type DCEP(B))
with the elements:
| Mode |
Frequency, c/d |
Semi-amplitude, IC mag |
Period, days |
Epoch, HJD |
| f0 |
2.363865 |
0.1733 |
0.423036 |
2452500.419 |
| f1 |
3.398055 |
0.0452 |
0.294286 |
2452500.303 |
| f1 + f0 |
5.761909 |
0.0164 |
0.1735536 |
2452500.340 |
Possible interaction frequencies: f1 + 2f0 (P = 0d.123067);
2f0 (P = 0d.211518).
The galactic latitude is b = +5°.046.
M–m = 0.33 P (fundamental mode pulsation).
4. The variability of OGLE-BLG-T2CEP-209 was discovered by Soszynski et al. (2011b).
The variable was classified as a BL Her variable star with the light elements:
Max = HJD 2455000.14712 + 1d.1812838 × E.
The cited authors give the secondary periods 0d.83298, 0d.48851,
0d.34559.
I re-analyzed the OGLE-III observations.
Actually, this is a double-mode Cepheid (type DCEP(B)),
pulsating in the fundamental and first overtone modes.
The presented secondary periods correspond to the first-overtone frequency
and interaction frequencies
f1 + f0, f1 + 2f0;
besides, we detected 8 more frequencies. The light elements are:
| Mode |
Frequency, c/d |
Semi-amplitude, IC mag |
Period, days |
Epoch, HJD |
| f0 |
0.846532 |
0.2080 |
1.18129 |
2453600.43 |
| f1 |
1.200509 |
0.0224 |
0.832980 |
2453600.197 |
| f1 + f0 |
2.047041 |
0.0182 |
0.488510 |
2453600.180 |
| f1 + 2f0 |
2.893594 |
0.0162 |
0.345591 |
2453600.240 |
| f1 – f0 |
0.353950 |
0.0078 |
2.82526 |
2453601.39 |
| f1 + 4f0 |
4.58665 |
0.0074 |
0.218024 |
2453600.433 |
| 4f0 – f1 |
2.185616 |
0.0047 |
0.457537 |
2453600.220 |
| 4f0 |
3.386238 |
0.0035 |
0.295313 |
2453600.301 |
| 3f0 – f1 |
1.33912 |
0.0035 |
0.74676 |
2453600.11 |
| 2f0 – f1 |
0.492577 |
0.0034 |
2.03014 |
2453601.83 |
| 5f0 + f1 |
5.43319 |
0.0030 |
0.184054 |
2453600.240 |
| 5f0 |
4.23268 |
0.0025 |
0.236257 |
2453600.301 |
Analyzing the OGLE data, we rejected observations of JD 2454221 that give a
too large scatter of the light curve.
The galactic latitude is b = –2°.142.
5. The variability of GSC 8455-00781 was discovered by Pojmanski (2002).
The ASAS-3 catalog lists the variable as a DSCT star with the elements:
Max = HJD 2451869.763 + 0d.11501 × E.
I re-investigated the star using the currently available ASAS-3, 1SWASP, and SSS
data.
It is actually a high-amplitude double-mode Delta Scuti star.
The light elements are:
| Mode |
Frequency, c/d |
Semi-amplitude,
WASP mag / ÑV(SSS) mag / V(ASAS) mag |
Period, days |
Epoch, HJD |
| f0 |
8.694858 |
0.249 / 0.225 / 0.231 |
0.1150105 |
2454200.102 |
| f1 |
11.24637 |
0.075 / 0.061 / 0.077 |
0.0889176 |
2454200.071 |
| f1 + f0 |
19.94121 |
0.047 / 0.042 / 0.049 |
0.0501474 |
2454200.0295 |
| f1 – f0 |
2.551470 |
0.038 / 0.035 / – |
0.391931 |
2454200.345 |
| 2f0 + f1 |
28.63606 |
0.025 / 0.023 / – |
0.0349210 |
2454200.0145 |
| 2f0 – f1 |
6.143336 |
0.013 / 0.020 / – |
0.162778 |
2454200.145 |
| 3f0 – f1 |
14.83829 |
0.007 / – / – |
0.0673932 |
2454200.0465 |
| f0 + 2f1 |
31.18753 |
0.011 / – / – |
0.0320641 |
2454200.0065 |
| 3f0 + f1 |
37.33098 |
0.008 / – / – |
0.0267874 |
2454200.0060 |
| 4f0 – f1 |
23.53312 |
0.006 / – / – |
0.0424933 |
2454200.0213 |
| 2f0 |
17.38967 |
0.003 / – / – |
0.0575054 |
2454200.0550 |
| 3f0 |
26.08433 |
0.002 / – / – |
0.0383372 |
2454200.0225 |
The period ratio of the first-overtone and fundamental modes is P1 / P0
= 0.7731.
J–K = 0.156 (2MASS).
From the ASAS-3 data, the variability range is 12m.9 – 13m.7
in the V band;
from the 1SWASP data, 13m.00 – 13m.91.
6. The variability of USNO-B1.0 1038-0622479 was discovered by Drake et al.
(2014; the Catalina surveys periodic variable star catalog).
The variable was classified as an RRC star with the period 0d.258489.
I re-analyzed the CSS observations, with the RR Lyrae nature and period of the
variable confirmed.
A secondary (non-radial) wave is superimposed on the first overtone pulsation.
The non-radial period is constant in all time interval of CSS data,
the first overtone period varies. The light elements:
First-overtone period (P1):
JD 2453500 – 2454500: HJD = 2454000.062 + 0d.258493 ×E;
JD 2454600 – 2455600: HJD = 2455000.175 + 0d.258477 ×E;
JD 2455600 – 2456600: HJD = 2456000.185 + 0d.258464 ×E.
Non-radial pulsation (P2):
JD 2453500 – 2456600: HJD = 2455000.222 + 0d.260058 ×E.
The amplitudes of the two oscillations vary:
| JD |
Semi-amplitude, ÑV mag
A1 / A2
|
| 2453500–2454500 |
0.133 / 0.078 |
| 2454600–2455600 |
0.159 / 0.057 |
| 2455600–2456600 |
0.177 / 0.048 |
The period ratio is P1 / P2 = 0.9939 – 0.9940.
J–K = 0.095 (2MASS); B–V = 0.321 (APASS).
Remarks:
I present a new investigation of six known variable stars. I analyzed all
observations
available for these stars in the
ASAS-3 (Pojmanski 2002),
SuperWASP
(Butters et al. 2010),
OGLE-III, and
Catalina
Surveys (Drake et al. 2009)
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 variables,
pulsating in the radial (type HADS(B) and CEP(B)) or radial and non-radial (type
RRC)
modes.
The period ratios P1 / P0 for stars Nos. 2 and 5
are typical for radially pulsating high-amplitude double-mode
Delta Scuti stars
(Petersen and Christensen-Dalsgaard 1996). The period ratios
P1 / P0 for stars Nos. 3 and 4 (Cepheids) are also
similar.
Along with the light curves,
I present power spectra of the variables, for the raw data and after subtraction
of the first-overtone (or fundamental mode) oscillations.
The structure of the power spectra shows that the secondary periods are real. In
certain cases, frequencies related to interactions between the two main modes
were
found (see
the Comments).
The tabulated coordinates of the variables were drawn from the 2MASS,
GSC2.3,
and USNO-B1.0 catalogs.
The SuperWASP observations are available as FITS tables, which were converted
into
ASCII tables using the
OMC2ASCII program
as described by Sokolovsky (2007).
Acknowledgements: The author wishes 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
Drake, A.J., Graham, M.J., Djorgovski, S.G., et al., 2014, Astrophys. J. Suppl.,
213, 9
Petersen, J.O., Christensen-Dalsgaard, J., 1996, Astron. Astrophys., 312, 463
Pojmanski, G., 2002, Acta Astronomica, 52, 397
Sokolovsky, K.V., 2007, Perem. Zvezdy Prilozh., 7, No. 30
Soszynski, I., Dziembowski, W.A., Udalski, A., et al., 2011a, Acta Astron., 61,
1
Soszynski, I., Udalski, A., Pietrukowicz, P., et al., 2011b, Acta Astronomica,
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285
