UY Puppis—A New Anomalous Z Cam Type Dwarf Nova

Volume 44 number 2 (2016)

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Rod Stubbings

Tetoora Road Observatory, 2643 Warragul-Korumburra Road, Tetoora Road 3821, Victoria, Australia; stubbo@sympac.com.au

Mike Simonsen

AAVSO Headquarters, 49 Bay State Road, Cambridge, MA 02138; mikesimonsen@aavso.org

Abstract

The defining characteristic of Z Cam stars are “standstills” in their light curves. Some Z Cams exhibit atypical behavior by going into outburst from a standstill. It has previously been suggested that UY Pup had been a Z Cam star, but it was ruled out due to its long-term light curve. However, in December 2015 UY Pup went into outburst and unexpectedly entered into a short standstill instead of returning to quiescence. Furthermore, UY Pup exhibited additional unusual behavior with two outbursts detected during its standstill. After this standstill UY Pup made a brief excursion to a quiescent state and slowly rose to a longer and well-defined standstill, where it again went into another outburst. Through comparative analysis, research, and observational data of UY Pup, it is evident and thus concluded that it is indeed a Z Cam star, which renders it one of only four known “anomalous Z Cam stars.”