Auflösung von magnetischen Oberflächendetails bei vollkonvektiven Sternen mit Hilfe tomographischer Linieninversion

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Previous Doppler images of evolved stars and of single pre-main-sequence stars reveal interesting differences in the types of magnetic activity seen in these two classes of objects and our Sun; the presence and nature of polar spots is one of the most striking differences found. With the advent of 8--10m-class telescopes, the time seems ripe now to extend the Doppler-imaging technique to thevery cool end of the main sequence. There, stars are thought tobe fully convective and therefore cannot possess an overshoot layerthat, as in the case of the Sun and similar stars, most likely harborsthe solar dynamo. Therefore, one could expect a fundamentally different magnetic-field topology than on the Sun and similar stars and thus a qualitatively different surface temperature distribution and new magnetic activity phenomena. Observing these differences would help to better understand the role of the solar tachocline for stellar dynamos in particular and dynamo theory in general.