My most recent observations of CY Aqr, an SXPHE variable star and a subdwarf located in the old disk of our Milky Way. These observations show a slightly longer fundamental period of 0.061046 ± 1.7e-5 d than that found in previous publications. The significance analysis of the fundamental period showed a false alarm probability of 0.000 ± 0.000, meaning the period calculated with the set of observations provided is very close to the actual fundamental.
This set comprises a total of 615 observations made with the Johnson V filter with my telescope installed in Starfront Observatories at Rockwood, TX. Each session was identified with a different color as follows:
Yes, I was aware of that paper. Thanks for sharing it anyway! Just wanted to share my latest results and encourage more observers to follow this star. In the last 200 days or so, I have been the only one uploading fresh data of CY Aqr. It will be great if you can contribute too!
As an aside, I note that CY Aqr has long been of interest to the AAVSO. As long ago as 1936, Leon Campbell (then AAVSO Recorder, what we now term Director) wrote in his Variable Star Notes that CY Aqr was the variable with shortest known period and that no period change had yet been found. (Popular Astronomy, volume 44, 394). Of course, since then, variables of shorter period have been discovered and a period change has been seen. CY Aqr was one of the few high amplitude variables of its type that could be usefully observed visually.
It is interesting for you to discuss a possible period change in CY Aqr. That latest paper would say that the period isn’t changing and that the variation in O-C is purely orbital. However, historically CY Aqr was also interpreted as having period breaks (abrupt period changes). As were many of the HADS (ex. XX Cyg). The idea of period breaks has long been considered a strong possibility in HADS. I agree it is worth watching more regularly. I’m not necessarily convinced with the results of that new paper.
I checked my spectral data and haven’t taken any on CY Aqr. I should have telescope time in January when I might be able to get an optical spectra (from H-beta to H-alpha) and perhaps JHK IR spectroscopy.
