  We report accurate measurements of the physical properties (mass, radius,
temperature) of components of the G+M eclipsing binary V530 Ori. The M-type
secondary shows a larger radius and a cooler temperature than predicted by
standard stellar evolution models, as has been found for many other low-mass
stars and ascribed to the effects of magnetic activity and/or spots. We show
that models from the Dartmouth series that incorporate magnetic fields are able
to match the observations with plausible field strengths of 1-2 kG, consistent
with a rough estimate we derive for that star.
