RX Cassiopeiae / RX Cas
Light curves and phase diagrams of the EB type eclipsing binary RX Cassiopeiae / RX Cas.
The following light curve and phase diagram were constructed from photometry of images taken with the Bradford Robotic Telescope Cluster Camera (BRT). The 30 black data points are from unfiltered images taken between 2012 September 23 and 2014 March 23, and the 35 red data points are from images taken between 2014 August 5 and 2016 October 1 using a V filter.
The following light curve and phase diagram were constructed from photometry of images taken with the Open University COAST telescope, a 14 inch/35 cm Schmidt-Cassegrain. Here, the 18 black data points are data from 2017 July 10 to 2017 August 7, while the 12 red data points are data from 2018 August 2 to 2018 August 24. All images were taken with a V filter.
Combining the above two sets of data generated the following light curve and phase diagram. Here, the black and red data points are the BRT data as above, while the blue and purple data points are the COAST data.
A black and white copy of the above phase diagram is given below.
The above phase diagrams were constructed using the period which subjectively gave the most self consistent plots, given the small number of data points for each group of images. It should also be noted that the COAST telescope was being calibrated during the period of the observations, and focusing could be inconsistent.
The catalogued period for this star is 32.32789d (GCVS), 32.31211d (AAVSO VSX) and 32.338d (Kreiner). There is significant o-c activity with this star (Kreiner). [Accessed 2018 October 29.]
Although the final phase diagram appears to show a lot of scatter, at least some of this appears to be due to changes in the light curve itself over different cycles. In the BRT data, both the 'black' and the 'red' data points, which were obtained about a year apart, suggest changes at phase 0.25, while the COAST data similarly shows a peak at phase 0.75, again in two sets of data obtained about a year apart. These may be due, at least in part, to the presence of an accretion disc and mass transfer between the components, as in W Ser type eclipsing binaries, see Anderson et al (1988) and Pustylnic et al (2007).
[This page updated 2018 October 29]