V1084 Her
V1084 Her is a CV star that is identified as a "possible IP" (Intermediate Polar, with both a strong magnetic field and an appreciable accretion disk). The orbital period is known to be 2.89344 hr, and previous studies have found possible spin periods (31.7 min) as well as superhumps (0.11696 day) and precession (~4 d). With our worldwide coverage of this source, in both the iTelescope network and our local observatory, we thought it would be a good opportunity to test our techniques and try to verify the spin period in particular.
Observations
(err: 0624, not 0623)
Light curve 06/16/2021
Period 06/16/2021
Light Curve 06/18/2021
06/18/2021
Light Curve 06/26/2021
Period 06/26/2021
Light Curve total data
Period total data
VStar into Peranso
The reported periods for this source correspond to frequencies of 8.29 Hz and 45.4 Hz. At this level of our analysis, although the data suggests both of these periods, they are quite inconclusive. Even combining the data together and using VStar obvious periodic structure was not there. As a test, the photometry was redone on only the longest windows, and an alternative analysis program was used (Peranso). During the reanalysis, we discovered one of the stars in the AAVSO sequence was actually a variable (findings which will be submitted to AAVSO). Skipping the star and running through Lomb-Scargle and ANOVA analysis in Peranso still did not reveal periods matching the expectation - but folding the data into periods of 3.1 hr, 3.6 hr, and 4.1 hr revealed phase plots which are strongly suggestive, shown below.
It is difficult to ascertain what these periods represent. A simple explanation is that they are higher harmonics of the ~30 min spin period, since they are spaced approximately 0.5 hr apart. However, this shorter period was not seen directly - the only short period signal was around 14 min (see below), but did not correspond to a convincing phase plot. The highest of these periods (4.1 hr) does correspond roughly to what is thought to be a superhump, but that does not explain the presence of the other two. Our observation windows are typically 2-4 hours, but this kind of aliasing is not indicated by the software (which uses a Spectral Window to determine what signals might be due to aliasing). At this time, we cannot explain the behavior of this source.
