Peremennye Zvezdy (Variable Stars) 45, No. 10, 2025 Received 10 July; accepted 25 August.	Article in PDF
	DOI: 10.24412/2221-0474-2025-45-99-105

CCD Observations of V729 Car

L. N. Berdnikov¹, A. Yu. Kniazev^1,2,3

1. Sternberg Astronomical Institute, 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

V729 Car was included in our program of CCD observations for Cepheids because this star was classified as a Cepheid (CEP, ) in the ASAS-3 catalog (Pojmanski 2003).

We observed V729 Car in four observing runs between 2010 and 2012 (JD 2455532 - 2456077) using the 76-cm telescope at the South African Astronomical Observatory (SAAO), Republic of South Africa. An SBIG CCD ST-10XME camera with filters of the Kron-Cousins photometric system (Cousins 1976) were employed.

The observation and reduction techniques used are described in Berdnikov et al. (2011). The resulting light curves, constructed with the elements , are shown in Fig. 1. All observations are given in Table 1 (see also the text file in the HTML version of the article) which contains 691 magnitude measurements with photometric errors close to 0.01 mag.

We used our observations to create the - and -band template curves, which are shown in Fig. 2. Additionally, we present the -band template curve based on observations from the ASAS-SN project (Jayasinghe et al. 2019). All template curves are given in Table 2, which lists the -, - and -band magnitudes of V729 Car at phases from 0 to 0.995 with a step of 0.005.

We will use our data to study the period stability of V729 Car.

The shape of the light curve of V729 Car remained constant for 25 years according to ASAS-3 and ASAS-SN data, which indicates that the star may be a classical Cepheid. A preliminary analysis of all available data confirms this classification. A detailed analysis will be published later, and if V729 Car does turn out to be a Cepheid, it will be the first ultra-long-period Cepheid found in our Galaxy.

Acknowledgments: The study was conducted under the state assignment of Lomonosov Moscow State University.

References:

Berdnikov, L. N., Kniazev, A. Yu., Sefako, R., et al., 2011, Astron. Rep., 55, 816

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

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

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

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