For 10 points, what type of stellar system contains two stars?
They aren't hot Jupiters, but magnetic torques cause long-period variation in the oblateness of these objects in the Applegate mechanism. Hans Ludendorff found Epsilon Aurigae to be one of these objects, which is likely in a disk of dust. Massive stars appear to evolve unusually slowly in a paradox named for one of these systems containing the "Demon Star". W Ursae Majoris and Beta Lyrae classes of these systems are ellipsoidal. (*) Light curves for one type of these systems have a large primary dip and a shallower secondary one. A small subgiant and large main sequence star make up their main Algol subclass. Eclipsing ones can be described as "semidetached" or "contact" due to Roche lobe overflow. The discovery of a white dwarf led to reclassification of Sirius as one of these systems. For 10 points, what type of stellar system contains two stars?
They aren't hot Jupiters, but magnetic torques cause long-period variation in the oblateness of these objects in the Applegate mechanism.
(eclipsing) binary star system [accept Algol-type binary or Algol variable or Algol paradox until "Algol" is read]