The Magnetic Binary GJ 65: A Test of Magnetic Diffusivity Effects

GJ 65 is a M dwarf binary system consisting of the two flare stars BL Cet (GJ 65A) and UV Cet (GJ 65B). Two teams of investigators have recently reported total magnetic fluxes corresponding to fields of 4.5 and 5.2 kG for GJ65A, and 5.8 and 6.7 kG for GJ65B: for each component, the magnetic results obtained by the two teams agree with each other within 1{\sigma}. For the first time, we can directly compare the predictions of our magneto-convective models, based on fitting observed stellar parameters, with measured field strengths. We find that our models agree with the observed field strengths provided the effects of finite conductivity are accounted for. Thus, GJ65 provides us an opportunity to use observations of field strengths to distinguish between the predictions of our models that assume perfect electrical conductivity and those that allow for finite conductivity.