Hereford Arizona Observatory found fluctuations in what type of main-sequence star in Cygnus?
Hereford Arizona Observatory Hereford Arizona Observatory (HAO), IAU-code G95, is an astronomical observatory, owned and operated by amateur astronomer Bruce L. Gary. Gary is the author of many publications related to astronomy, including "Exoplanet Observing for Amateurs" (2008), currently available in a second edition (2009). Observational studies of unusual starlight fluctuations in KIC 8462852 and WD 1145+017 are recent interests.
Double periodic variable A Double Periodic Variable (DPV) is a type of binary star. As the name implies, the systems vary in brightness not only due to eclipses of one star by the other, but also on a cycle of roughly 33 times longer than the orbit. The star gaining mass from the other has a thick disk of material surrounding it, and the systems apparently lose mass cyclically into the interstellar medium over time. The cause for the secondary longer variability still is not established. The stars are rare, with 21 systems found in the Galaxy and more than 170 in the Magellanic Clouds (Abril 2016).