Double periodic variable

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A double periodic variable 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.[1] The stars are extremely rare, with less than fifteen candidates known as of July 2014.


The following list contains selected double periodic variables that are of interest to amateur or professional astronomy. Unless otherwise noted, the given magnitudes are in the V-band.

Eclipse period
(in days)
V393 Scorpii 7.39 8.31 7.72 B3III
AU Monocerotis 8.20 9.16 11.11 B5IV+F8-G0II-III


  1. ^ Otero, S. A.; Watson, C.; Wils, P. "Variable Star Type Designations in the VSX". AAVSO Website. American Association of Variable Star Observers. Retrieved 11 May 2014.