Astron. Astrophys. 326, 155-160
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Bernoulli's equation and the contact binaries
Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg, Germany
Received 31 May 1996 / Accepted 31 January 1997
In a recent paper Bernoulli's equation has been so interpreted as to mean that the Jacobi energy is constant over the surface of a stationary contact binary. We argue that Bernoulli's result can not be interpreted in this way and show that such a constraint on the Jacobi energy is in general not compatible with stationarity.
We also show that, under isentropic conditions, a surface potential gradient can not cause a steady net flow of material across the system's surface plus a deeper return flow.
An apparent paradox raised by 'stationary solutions' for AB Andromedae can be resolved when it is recognized that Bernoulli's equation does not provide a simple recipe for calculating mean potential differences between contact components.
Key words: stars: binaries: close - hydrodynamics
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© European Southern Observatory (ESO) 1997
Online publication: September 9, 1997