We measured the angular diameter of the exoplanet host star \epsilon Eridani using the Navy Optical Interferometer .
We determined its physical radius , effective temperature , and mass by combining our measurement with the star ’ s parallax , photometry from the literature , and the Yonsei–Yale isochrones ( 36 ) , respectively .
We used the resulting stellar mass of 0.82 \pm 0.05 M _ { \odot } plus the mass function from Benedict et al .
( 4 ) to calculate the planet ’ s mass , which is 1.53 \pm 0.22 M _ { Jupiter } .
Using our new effective temperature , we also estimated the extent of the habitable zone for the system .