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The active K2 dwarf epsilon Eri has been extensively characterized, both as ayoung solar analog and more recently as an exoplanet host star. As one of thenearest and brightest stars in the sky, it provides an unparalleled opportunityto constrain stellar dynamo theory beyond the Sun. We confirm and document the3 year magnetic activity cycle in epsilon Eri originally reported by Hatzes andcoworkers, and we examine the archival data from previous observations spanning45 years. The data show coexisting 3 year and 13 year periods leading into abroad activity minimum that resembles a Maunder minimum-like state, followed bythe resurgence of a coherent 3 year cycle. The nearly continuous activityrecord suggests the simultaneous operation of two stellar dynamos with cycleperiods of 2.95+/-0.03 years and 12.7+/-0.3 years, which by analogy with thesolar case suggests a revised identification of the dynamo mechanisms that areresponsible for the so-called "active" and "inactive" sequences as proposed byBohm-Vitense. Finally, based on the observed properties of epsilon Eri we arguethat the rotational history of the Sun is what makes it an outlier in thecontext of magnetic cycles observed in other stars (as also suggested by its Lidepletion), and that a Jovian-mass companion cannot be the universalexplanation for the solar peculiarities.

Magnetic Activity Cycles in the Exoplanet Host Star epsilon Eridani