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RY Ursae Majoris

Due to the New England winter storm currently affecting the area, phone coverage at the AAVSO may be much reduced until Wednesday. The staff is still available via email, and we suggest using that method to contact us if you need assistance.

RY UMa is a semiregular variable of type SRa, meaning it has reasonably stable pulsations over part of its history, but with lower amplitude than their Mira-type cousins.  In this case, RY UMa has a well-defined pulsation period around 310 days, but it also has a supercycle of several thousand days during which the pulsations apparently cease.  It's not clear why this is the case.  RY is a bright variable for the northern hemisphere, well within range of most observers including binocular observers.

Prepared By: Matthew Templeton
AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484