Journal "Peremennye Zvezdy"

Peremennye Zvezdy (Variable Stars) 33, No. 6, 2013

Received 11 July; accepted 17 July.

Article in PDF

A Photometric Study of the Pulsating Variable Star TYC 0075 01143 1

A.V. Khruslov¹, A.V. Kusakin²

Institute of Astronomy, Russian Academy of Sciences, Moscow, Russia, e-mail: khruslov@bk.ru;
Fesenkov Astrophysical Institute, Almaty, Kazakhstan, e-mail: un7gbd@gmail.com

We present the results of our new observations of TYC 0075 01143 1, a recently discovered double-mode

Scuti variable. We improved the frequencies

and

and pulsation amplitudes, detected the interaction frequencies

, and a possible nonradial frequency

1. Introduction

In this paper, we present the results of our study of a multiple-periodicity

Scuti variable star TYC 0075 01143 1. Its coordinates in the Tycho-2 catalog are

(J2000.0).

Variability of TYC 0075 01143 1 = ASAS 042606+0126.4 was detected in the ASAS-3 project (Pojmanski 2002). In the ASAS catalog, the classification of the variable is EC/DSCT (a contact eclipsing binary or a Scuti variable); a period is also given there. Kruslov (2011) confirmed that TYC 0075 01143 1 belonged to Scuti stars; he also detected the double-mode character of brightness variations and suggested the following light elements:

Preliminary results from our new CCD observations were published by Khruslov et al. (2012). In the present paper, we use a much longer series of observations that made it possible to detect new interaction frequencies and a possible nonradial frequency, .

2. Observations

We acquired new CCD observations of TYC 0075 01143 1. Our observations were performed at the Tien Shan Astronomical Observatory of the V.G. Fesenkov Astrophysical Institute, at the altitude of 2750 m above the sea level, using a Ritchey-Chretien telescope designed by V.B. Sekirov. The telescope's mirror diameter is 360 mm, the focal length of the system being 1440 mm. The detector was an ST-402 SBIG CCD camera. The observations were made on 11 nights between December 17, 2011 and November 20, 2012 (JD 2455913-2456252); in total, we obtained 1718 brightness estimates. All frames had 60-second exposure times in Johnson's

band. For flat-fielding, we observed morning or evening twilight sky. The dark current was taken into account during the observations; the chip was cooled to

C. Reductions made use of the MuniWin code.

The finding chart (Fig. 1) identifies the variable star, comparison star, and check star. The comparison star was GSC 00075-01862 and the check star, GSC 00075-01079. The magnitudes of these stars in the GSC2.3 catalog are respectively and .

Our observations are available online in the html version of this paper.

Fig. 1. The finding chart of TYC 0075 01143 1.

3. Results

We analyzed the time series using Deeming's method implemented in the WinEfk code written by V.P. Goranskij. Using our new observations of TYC 0075 01143 1, we improved the frequencies

and

, detected oscillations corresponding to interaction between

and

; we also found a possible nonradial frequency

. The results are presented in the Table.

Table. Detected frequencies

Mode	Frequency, c/d	-band semi-amplitude,	Period, days	Epoch, HJD
		mag
	13.435398	0.126	0.07443025	2456100.0083
	17.270241	0.074	0.05790307	2456100.0133
	30.70565	0.024	0.0325673	2456100.0084
	3.834915	0.016	0.260762	2456100.017
	25.68687	0.016	0.0389304	2456100.0065

The light curves of TYC 0075 01143 1 are displayed in Fig. 2. The -band range of TYC 0075 01143 1 is . The period ratio is typical of high-amplitude double-mode Scuti stars radially pulsating in the fundamental and first overtone modes (Petersen & Christensen-Dalsgaard 1996).

Fig. 2. The light curves of TYC 0075 01143 1. Upper panels: raw data; lower panels: the folded light curves with the other variation pre-whitened.

Along with the light curves, we present power spectra of TYC 0075 01143 1, for the raw data and after subtraction of the fundamental-mode oscillations (see Fig. 3). Figure 4 exhibits light-curve variations from one cycle to another during the same night, typical of high-amplitude double-mode Scuti variables.

The frequency is identified rather reliably, its amplitude is close to that for the frequency . The structure of the power spectra (Fig. 5) leaves no doubt that is a real frequency. However, we cannot completely rule out that the real frequency is a one-day alias of the tabulated , namely (the corresponding period being 00374673).

Acknowledgements: The authors are grateful to Dr. V.P. Goranskij for providing software for the light-curve analysis. We wish to thank M.A. Krugov for technical assistance during the observations and Dr. N.N. Samus for helpful discussions. This study was supported by the Russian Foundation for Basic Research and by the Programme "Non-stationary Phenomena of Objects in the Universe" of the Presidium of Russian Academy of Sciences.

Fig. 3. Power spectra of TYC 0075 01143 1 for the frequencies and .

Fig. 4. Observations of TYC 0075 01143 1 acquired during a single night of November 20, 2012 (JD 2456252).

Fig. 5. The power spectrum for the frequency . All the other detected frequencies were pre-whitened.

References:

Khruslov, A.V. 2011, PZP, 11, 30

Khruslov, A.V., Samus, N.N., Kokumbaeva, R.I., Kusakin, A.V. 2012, Communications from the National Academy of Sciences of Kazakhstan, Physics and Mathematics Series, No. 3, 25

Petersen, J.O., Christensen-Dalsgaard, J. 1996, Astron. and Astrophys., 312, 463

Pojmanski, G., 2002, Acta Astronomica, 52, 397

A Photometric Study of the Pulsating Variable Star TYC 0075 01143 1

A.V. Khruslov1, A.V. Kusakin2

1. Introduction

2. Observations

3. Results

A.V. Khruslov¹, A.V. Kusakin²