VZ Lib: analysis of Tsesevitch (1954)

The fist observations of VZ Lib were reported in Tsesevich B.P. (1954) Izvestiya Astronomicheskoy Observatorii 4 196 (may be downloaded from http://lib.onu.ua/en/ukrayinska-odessa-astronomical-publications).

Although the paper is written in Russian that, unfortunatly, I cannot read, I analyzed the photometry tables. The observations span from 1937 to 1944. I derive a ToM for each season:

Season 1937

36 observations are reported. A phase plot is shown below. The phase plot is very insensitive to the period, I use the period reported in my 2009 publication and another from the ephemeride (2) of Liu et al (2019), with the same result.

As the above plot does not show clear minima, I take the average of 3 measurements for each phase point:

This allows the determination of the ToM: 2428715.301 ± 0.005 HJD.

Season 1938

68 observations:





ToM: 2429055.350 ± 0.003 HJD.

Season 1942

68 observations:



(No need to average).

ToM: 2430509.95 ± 0.01 HJD.

Season 1943

72 observations:



(No need to average).

ToM: 2430900.292 ± 0.005 HJD.

Season 1944

127 observations:





ToM: 2431253.377 ± 0.003 HJD.