BB Cephei / BB Cep
Light curves and phase diagrams of the EA type eclipsing binary BB Cephei / BB Cep.
The COAST (1) light curve and phase diagram were constructed from photometry of 106 images taken with the Open University COAST telescope (a 14 inch / 35 cm Schmidt-Cassegrain) through a V filter between 2017 July 6 and 2018 January 25.
Previous observations with the Bradford Robotic Telescope Cluster Camera with a V filter (BRT), between 2014 July 12 and 2016 January 8, result in the following light curve.
Combining the above two sets of results generates the following light curve and phase diagram. The BRT observations are in red, the COAST observations are in black.
The catalogue period for this star is 30.1856d (GCVS, AAVSO VSX) and 30.1862d (Kreiner). The above phase diagrams were plotted using the former value. There is little o-c activity with this star (Kreiner).
The COAST results clearly show that the maximum from the primary to the secondary minimum (phase ~0.25) is essentially flat, while the maximum from the secondary to the primary minimum (phase ~0.75) is 'humped'. The scarce BRT data, from two years earlier, is not consistent with this. This might be due to poor quality data, or possibly there might be changes to the shape of the light curve over timescales of a few years. More observations and analysis needed.
[This page updated 2018 August 22]