Fig. 1

The O−C diagram for the primary minima calculated from the linear elements (Eq. (1)). The abscissa is given in units of orbit number, with the origin defined on HJD 2 432 456.671 (1947 Sept. 28) and adopting P0 = 1.64124d. The ordinate is in units of fraction of orbital period. The error bars indicate an assumed precision of ±0.005 in orbital fraction, which corresponds to ~11 min. The red squares denote values from 1947 to 1971 and the blue diamonds denote data from 1971–2014. The last point corresponds to Skinner et al. (2015), who have determined the time of minimum to a precision of 20 s.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.