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Studies of Yellow SemiRegular (SRd) Variables


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John R. Percy

David L. Kolin

Erindale Campus

Department of Astronomy

University of Toronto

Mississauga ON, Canada L5L lC6


Presented at the 88th AAVSO Spring Meeting, July 3, 1999




We have used the Hipparcos database of epoch photometry to study the variability of several yellow semiregular (SRd) variables. For some of the stars (V487 Cas, RW Cep, BM Sco, CE Vir), the results were inconclusive. For SX Lac and TY Vir, the periods found were consistent with the General Catalogue of Variable Stars (190 and 50 days, respectively). For UU Her, the known periods of about 45 and 72 days were recovered. For WY And, RU Cep, and SX Her, reliable periods were found; we used archival data to construct (O-C) diagrams to study both random and systematic period changes in these three stars.

Link to ADS abstract, article and citation information

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