Peremennye Zvezdy (Variable Stars) 40, No. 9, 2020 Received 17 November; accepted 25 November.	Article in PDF
	DOI: 10.24411/2221-0474-2020-10010

BVI_c CCD Observations of RR Lyrae variable SU Hor

L.N. Berdnikov¹, A.Yu. Kniazev^1,2,3, A.K. Dambis¹, V.V. Kravtsov¹

1. Sternberg Astronomical Institute, Lomonosov Moscow State University, Universitetskij pr. 13, Moscow 119992, Russia

2. South African Astronomical Observatory, P.O. Box 9, Observatory, Cape Town, 7935 South Africa

3. Southern African Large Telescope Foundation, P.O. Box 9, Observatory, Cape Town, 7935 South Africa

1. Introduction

In 2009, we started a program aimed at obtaining photometric observations for RR Lyrae variables that had no reliable light curves. The first results of our photometry were published by Berdnikov et al. (2012) who suspected the presence of Blazhko effect (Blazhko, 1907) for several stars, including SU Hor.

To study the Blazhko effect, we continued to observe SU Hor. Here we present the results of our photometry.

2. Observational data

We performed new CCD observations of SU Hor in 2012-2014 (in the JD 2455896-2456679 range) with the 76-cm telescope of the South African Astronomical Observatory (SAAO) using a SBIG CCD ST-10XME camera equipped with -band filters of the Kron-Cousins photometric system (Cousins, 1976). A description of the observing data reduction technique can be found in our previous paper (Berdnikov, 2012). We acquired a total of 2900 CCD frames, where extracted magnitudes of SU Hor had errors close to 0.01 mag.

We also used the Las Cumbres Observatory Global Telescope (LCOGT) Network (Brown et al., 2013) to acquire 1065 CCD frames during the time interval JD 2456633-2456689. We reduce LCOGT observations by performing differential photometry relative to secondary standards whose magnitudes we determined based on observations made in SAAO; the photometric errors of these observations are close to 0.02 mag.

All observations are available in a text file in the html version of the paper.

The light curves are shown in Fig. 1, where the big scatter of points supports the presence of Blazhko effect. We plan to use our data to search for the Blazhko effect period.

On the base of our observations we constructed the -, -, and -band template curves, presented in a text file in the html version of the paper and Fig. 2; together with them, we present the -band template curve, based on observations from the ASAS-SN catalog (Jayasinghe et al., 2019). Table 2 lists the -, -, -, and -band magnitudes of SU Hor at phases from 0 to 0.995 with a step of 0.005.

We plan to use these templates to study the behavior of pulsating period of SU Hor.

Acknowledgments: This work was supported by the Russian Foundation for Basic Research (project nos. 18-02-00890 and 19-02-00611).

References:

Berdnikov, L.N., Vozyakova, O.V., Kniazev, A.Yu., et al. 2012, Astron. Rep., 56, 290

Blazhko, S. 1907, Astron. Nachr., 175, 325

Brown, T.M., Baliber, N., Bianco, F.B., et al. 2013, Publ. Astron. Soc. Pacif., 125, 1031

Cousins, A.W.J. 1976, Mem. RAS, 81, 25

Jayasinghe, T., Stanek, K.Z., Kochanek, C.S., et al. 2019, Mon. Not. Roy. Astron. Soc., 485, 961

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