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Paper: Doppler Imaging of Active Binary Stars
Volume: 318, Spectroscopically and Spatially Resolving the Components of Close Binary Stars
Page: 69
Authors: Strassmeier, K.G.
Abstract: Binaries can be used as astrophysical laboratories to study a much larger range of parameters than nature would normally foresee for a single star. A good example is the evolution of the stellar magnetic field and its tracers. Solar analogy tells us that the surface starspot distribution, and its variation in time, is a fingerprint of the underlying dynamo process and its subsequent magnetic-field eruption as bipolar spots or spot groups. But is this also true for more massive and less massive stars, even for fully convective stars? I show how astronomers nowadays resolve a stellar surface by means of a tomographic imaging technique and recover the surface temperature distribution as a tracer of the magnetic field and, of course, also emphasize its limitations. The technique requires relatively high-resolution high-S/N spectra well sampled over a rotation period of the star and is, so far, mainly technology driven. Therefore, I will present also an update of future instrumentation for stellar-activity work. Finally, I focus the scientific discussion on three recent studies of active double-lined spectroscopic binaries as three representative proxies of stellar activity throughout the HR-diagram.
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