Peremennye Zvezdy

"Peremennye Zvezdy",
Prilozhenie
,
vol. 14, N 1 (2014)

New Elements for Double- and Multimode High-Amplitude Delta Scuti Variables

A. V. Khruslov
Institute of Astronomy, Russian Academy of Sciences, Moscow, Russia

Received:   3.12.2013;   accepted:   13.01.2014
(E-mail for contact: khruslov@bk.ru)


#NameOtherCoord (J2000)TypeMaxMinSystemPeriodEpoch (JD)typeSpCommentL.CurveFind.ChartData
1 TYC 2420 00093 106 12 13.90, +31 48 24.4HADS(B)12.8913.20WASP(see Comments)(see Comments)max Comm. 11.PNGchart1.PNG1SWASP_data_1.txt
2 TYC 7805 00075 114 28 21.58, -38 12 14.5HADS9.8910.09WASP(see Comments)(see Comments)max Comm. 22.PNGchart2.PNG1SWASP_data_2.txt ASAS 142822-3812.3
3 TYC 8699 00544 115 23 15.43, -56 03 43.2HADS(B)11.2211.57V(see Comments)(see Comments)max Comm. 33.PNGchart3.PNGASAS 152315-5603.7
4 GSC 3881-0087416 29 40.31, +57 20 33.3HADS(B)13.2413.48WASP(see Comments)(see Comments)max Comm. 44.PNGchart4.PNG1SWASP_data_4.txt CSS_data_4.txt
5NSV 09856GSC 7378-01754, HV 1030917 56 00.20, -30 42 46.6HADS(B)12.1012.50V(see Comments)(see Comments)max Comm. 55.PNG ASAS 175600-3042.8
6 GSC 6905-0164120 10 22.51, -23 10 59.7HADS(B)14.8415.29CV(see Comments)(see Comments)max Comm. 66.PNGchart6.PNGCSS_SSS_data_6.txt
7 TYC 2706 01244 121 12 53.68, +33 17 34.3HADS(B)10.4710.69WASP(see Comments)(see Comments)max Comm. 77.PNGchart7.PNG1SWASP_data_7.txt NSVS 8673444 NSVS 8691341

Comments:


1. The variability of GSC 2420-00093 was discovered by Přibik & Brat (2009). The variable was classified as a HADS(B) variable, pulsating in the fundamental and first overtone modes with one additional frequency. Přibik & Brat give the following light elements:
HJD(max) 2454758.4180 + 0.07105196×E (fundamental mode period);
HJD(max) 2454758.4072 + 0.05503008×E (first overtone period);
HJD(max) 2454758.4170 + 0.04250400×E (additional period).
I re-analyzed 1SWASP data and confirm the HADS(B) nature of this variable as well as two of the three periods (the fundamental and first-overtone ones). It is actually a triple-mode HADS(B) star, pulsating in the fundamental, first, and second overtone modes. The additional period suggested by Přibik & Brat (2009) is a one-day alias of the real second overtone period (see the Table). —onfidently identified are also frequencies related to interactions between the three main modes: f1 – f0, f2 – f0, f1 + f0, f2 + f0. The light elements are:

ModeFrequency, c/d Semi-amplitude, WASP mag Period, days Epoch, HJD
f0 14.07349 0.079 0.0710556 2454100.533
f1 18.17151 0.027 0.0550312 2454100.525
f2 22.52663 0.016 0.0443919 2454100.5395
f1 – f0 4.09803 0.009 0.24402(0) 2454100.523
f2 – f0 8.45316 0.005 0.118299 2454100.576
f1 + f0 32.24496 0.005 0.0310126 2454100.5255
f2 + f0 36.6001 0.004 0.0273223 2454100.508

P1/P0 = 0.7745, P2/P1 = 0.8067. B–V = 0.010 (Tycho2), J–K = 0.248 (2MASS). In our Galaxy, this is the fourth case of a triple-mode HADS(B) star, along with the previosly known DO CMi (Wils et al. 2008), V829 Aql (Handler et al. 1998), and the newly discovered TYC 3144-595-1 (Ulusoy et al. 2013).

2. The variability of TYC 7805 00075 1 was discovered by Pojmanski (2002). The ASAS-3 catalog lists the variable as a DSCT star with the elements HJD(max) 2451903.31 + 0.166993×E. I reinvestigated the star using the currently available 1SWASP and ASAS-3 data. I confirm the delta Scuti nature and the fundamental period of this variable. A secondary wave (possibly nonradial) is superimposed on the fundamental pulsation. The light elements are:

ModeFrequency, c/d Semi-amplitude, mag Period, days Epoch, HJD
f1 5.988124 0.081 (WASP), 0.078 (V, ASAS) 0.1669972 2455200.003
f2 9.69979 0.007 (WASP), 0.007 (V, ASAS) 0.103095 2455200.067

The period ratio is: P2/P1 = 0.6173. f2 is possibly a nonradial pulsation; its identification with the second overtone mode is not excluded. Also not excluded are other weak pulsations, with the periods of 0.0997346 days, 0.1822313 days, 0.0995966 days and small amplitudes. B–V = 0.411 (Tycho2), J–K = 0.174 (2MASS). From the ASAS-3 data, the variability range is 9m.66 – 9m.89 (V). The WASP data from different time intervals exhibit considerable differences of the mean brightness; my analysis was based on one of them, JD2454148–2454274.

3. The variability of TYC 8699 00544 1 was discovered by Pojmanski (2002). The ASAS-3 catalog lists the variable as a DSCT star with the elements HJD(max) 2451920.154 + 0.126749×E. I reinvestigated the star using the currently available ASAS-3 data. It is actually a high-amplitude double-mode Delta Scuti star. The light elements are:

ModeFrequency, c/d Semi-amplitude, V mag Period, days Epoch, HJD
f0 7.889752 0.107 0.1267467 2453600.5683
f1 10.238370 0.030 0.0976718 2453600.577

The period ratio of the first overtone and fundamental modes is P1 / P0 = 0.7706. B–V = 0.397 (Tycho2), J–K = 0.224 (2MASS).

4. The variability of GSC 3881-00874 was reported in 2012 by P. Wils in the VSX database (BPS BS 16084-151) according to 1SWASP data (Butters et al. 2010). The star was classified by the discoverer as a DSCT star with the light elements: HJD(max) 2454286.400 + 0.061144×E. I reinvestigated the star using the currently available 1SWASP data. It is actually a high-amplitude double-mode Delta Scuti star. The light elements are:

ModeFrequency, c/d Semi-amplitude, WASP mag Period, days Epoch, HJD
f0 16.355196 0.072 0.06114265 2454450.5110
f1 21.05112 0.020 0.0475034 2454450.5245
f1 + f0 37.40625 0.006 0.0267335 2454450.5172
fN 16.46578 0.005 0.0607320 2454450.5493

The period ratio of the first overtone and fundamental modes is P1 / P0 = 0.7769. J–K = 0.156 (2MASS). From the CSS data, the variability range is 13m.09 – 13m.25 (CV).

5. The delta Scuti nature of NSV 09856 = HV 10309 was reported by Kazarovets & Pastukhova (2013) according to ASAS-3 data. Their light elements are: HJD(max) 2453581.7052 + 0.1184880×E. I re-analyzed the ASAS-3 data. It is actually a triple-mode HADS(B) star, pulsating in the fundamental, first-overtone, and second-overtone modes. In our Galaxy, it is the fifth case of a triple-mode HADS(B) star. The light elements are:

ModeFrequency, c/d Semi-amplitude, V mag Period, days Epoch, HJD
f0 8.439673 0.090 0.1184880 2453581.7052
f1 10.95611 0.066 0.0912733 2453581.7065
f2 13.65426 0.027 0.0732372 2453581.7080
f1 – f0 2.516521 0.024 0.397374 2453581.715
f1 + f0 19.39582 0.018 0.0515575 2453581.7497

P1 / f0 = 0.7703; P2 / f1 = 0.8024; P2 / f0 = 0.6181. J–K = 0.239 (2MASS).

6. The variability of GSC 6905-01641 was reported by Keller et al. (2008, SEKBO 112944.737). The variable was classified as a possible RR Lyrae star (RR:) without light elements. According to the Siding Springs Survey data (Drake et al. 2009), it is a double-mode HADS star. The light elements are:

ModeFrequency, c/d Semi-amplitude, —V mag Period, days Epoch, HJD
f0 14.53469 0.147 0.0688009 2455000.5337
f1 18.76433 0.039 0.0532926 2455000.5470

The period ratio is P1 / P0 = 0.7746. J–K = 0.121 (2MASS).

7. The variability of TYC 2706 01244 1 was reported in 2011 by Gregor Srdoc in the VSX database (VSX J211253.6+331734), according to 1SWASP data (Butters et al. 2010). The star was classified by the discoverer as a HADS star with the light elements: HJD(max) 2454318.4732 + 0.08785×E. I re-analyzed 1SWASP and NSVS data and found out that the variable was actually a double-mode HADS star. The light elements are:

ModeFrequency, c/d Semi-amplitude, mag Period, days Epoch, HJD
f2 11.38334 0.060 (WASP), 0.052 (R, NSVS) 0.0878477 2454340.557
f1 9.49652 0.040 (WASP), 0.044 (R, NSVS) 0.105302 2454340.558
f2 + f1 20.8798 0.009 (WASP) 0.0478932 2454340.5460
f2 – f1 1.8882 0.004 (WASP) 0.5296 2454340.53
2f2 + f1 32.2630 0.004 (WASP) 0.0309953 2454340.5152
f2 + 2f1 30.3759 0.002 (WASP) 0.0329208 2454340.5115

The period ratio is P2 / P1 = 0.8342. Radial pulsations in the second and third overtones are not excluded. B–V = 0.402 (Tycho2), J–K = 0.210 (2MASS).

Remarks:
I present an investigation of seven high-amplitude Delta Scuti variables.

I re-analysed all observations available for these stars from the SuperWASP (Butters et al. 2010), ASAS-3 (Pojmanski 2002), ROTSE-I/NSVS (Woźniak et al. 2004) 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- or multimode high-amplitude Delta Scuti stars.

The period ratios P1/P0 and P2/P1 are typical for radially pulsating high-amplitude double-mode and multi-mode Delta Scuti stars (Petersen & Christensen-Dalsgaard 1996). In one case, we possibly encounter nonradial pulsations (or F and 2O modes), and one case possibly corresponds to pulsations in the second and third overtone modes. In certain cases, multiple frequencies or frequencies related to interactions between the two main modes were found (see the Comments).

The coordinates were drawn either from the Tycho-2 or from the 2MASS 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: I am grateful to Dr. K.V. Sokolovsky for his advice concerning data retrieving. I 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. and Astrophys., 520, L10
Drake, A.J., Djorgovski, S.G., Mahabal, A., et al., 2009, Astrophys. J., 696, 870
Handler, G., Pikall, H. and Diethelm, R., 1998, Inform. Bull. Var. Stars, No. 4549
Kazarovets, E.V., Pastukhova, E.N., 2013, Perem. Zvezdy Prilozh., 13, No. 20
Keller, S.C., Murphy, S., Prior, S., et al., 2008, Astrophys. J., 678, 851
Petersen, J.O., Christensen-Dalsgaard, J., 1996, Astron. and Astrophys., 312, 463
Pojmanski, G., 2002, Acta Astronomica, 52, 397
Přibik, V. , Brat, L., 2009, Open European Journal on Variable Stars, 109, 4
Sokolovsky, K.V., 2007, Perem. Zvezdy Prilozh., 7, No. 30
Ulusoy, C., Ulaş, B., Gülmez, T., et al., 2013, Monthly Not. Roy. Astron. Soc., 433, 394
Wils, P., Rozakis, I., Kleidis, S., et al., 2008, Astron. and Astrophys., 478, 865
Woźniak, P.R., Vestrand, W.T., Akerlof, C.W., et al., 2004, Astron. J., 127, 2436



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