IP Peg: long-term changes

(vsnet 749)

Changes of the Outbursts of the Dwarf Nova IP Peg

A.V. Halevin
Department of Astronomy, Odessa State University
T.G.Shevchenko Park, Odessa 270014 Ukraine
E-mail: root@astro.odessa.ua

The dwarf Nova IP Peg was studied on 350 photographic plates of the Odessa Sky Patrol obtained in 1957-1989. 14 outbursts were registered with a width >= 4 days. The long term changes of the quiescent brightness are studied. An abrupt (<200 days) change of the mean brightness from 14.7m (pg) to 15.7m in 1972 (JD 2442000) was registered followed by a smooth decrease to 16.0m in 1987. This phenomenon may be explained by an abrupt decrease of the accretion rate in this cataclysmic variable.

It may be noted that E.I.Orlovskij and V.P.Goranskij (Peremennye Zvezdy, 22, 3) detected an abrupt decrease of the hump at the phase curve from 1.5 mag downto 1 mag and a decrease of the mean brightness of the system by 0.2 mag in 1980--81.

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