Contact binary systems (also known as W UMa systems) consist of a pair of hydrogen-burning dwarf stars orbiting each other so closely that they share a common envelope. Although they are relatively common, there is as yet no established consensus on
the principle evolutionary questions surrounding them: how do they form, how do they evolve over time, what do they become? One observational clue to their evolutionary history has been the abrupt termination of the orbital period distribution around 5.2 hours. We have undertaken an observational study of this by 1) discovery of fast W UMa systems in our Calvin-Rehoboth Observatory data archive, 2) follow-up with the Calvin-Rehoboth Observatory of candidate fast systems from the Catalina Sky Survey, and 3) follow-up of other reports of potentially fast systems in other recently published surveys. We find the follow-up to have been particularly important as many surveys taken for other purposes lead to ambiguous or incorrect claims for periods less than five hours. Our results to date may be characterized as showing two distinct components: the steeply decaying tail associated with the previously known cutoff along with a low-amplitude, but apparently uniform distribution that extends down to 3.6 hours. The confirmation at greater sensitivity of the abruptness of the cutoff seems to imply that the dominant mechanism for system formation (or the mechanism that determines system lifetime) does have a strong period dependence. At the same time, there appears to be a second mechanism at work as well which leads to the formation of the ultrafast component of the histogram.
We have identified some two-hundred new variable stars in a systematic study of a data archive obtained with the Calvin-Rehoboth observatory. Of these, we present five close binaries showing behaviors presumably due to star spots or other magnetic ac
tivity. For context, we first present two new RS CVn systems whose behavior can be readily attribute to star spots. Then we present three new close binary systems that are rather atypical, with light curves that are changing over time in ways not easily understood in terms of star spot activity generally associated with magnetically active binary systems called RS CVn systems. Two of these three are contact binaries that exhibit gradual changes in average brightness without noticeable changes in light curve shape. A third system has shown such large changes in light curve morphology that we speculate this may be a rare instance of a system that transitions back and forth between contact and noncontact configurations, perhaps driven by magnetic cycles in at least one member of the binary.
With recent developments in imaging and computer technology the amount of available astronomical data has increased dramatically. Although most of these data sets are not dedicated to the study of variable stars much of it can, with the application o
f proper software tools, be recycled for the discovery of new variable stars. Fits Viewer and Data Retrieval System is a new software package that takes advantage of modern computer advances to search astronomical data for new variable stars. More than 200 new variable stars have been found in a data set taken with the Calvin College Rehoboth Robotic telescope using FVDRS. One particularly interesting example is a very fast subdwarf B with a 95 minute orbital period, the fastest currently known of the HW Vir type.
