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Discovery of a Magnetic White Dwarf in the Symbiotic Binary Z Andromedae

J. L. Sokoloski·Lars Bildsten
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Abstract

We report the first result from our survey of rapid variability in symbiotic binaries: the discovery of a persistent oscillation at P=1682.6 +- 0.6 s in the optical emission from the prototype symbiotic, Z Andromedae. The oscillation was detected on all 8 occasions on which the source was observed over a timespan of nearly a year, making it the first such persistent periodic pulse found in a symbiotic binary. The amplitude was typically 2 - 5 mmag, and it was correlated with the optical brightness during a relatively small outburst of the system. The most natural explanation is that the oscillation arises from the rotation of an accreting, magnetic (B_S > 10^5 G) white dwarf. This discovery constrains the outburst mechanisms, since the oscillation emission region near the surface of the white dwarf was visible during the outburst.

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J. L. Sokoloski, Lars Bildsten. 1998-12-16. Discovery of a Magnetic White Dwarf in the Symbiotic Binary Z Andromedae. https://doi.org/10.1086/307234

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