We used the CHARA Array to directly measure the angular diameter of HD 69830 , home to three Neptune mass planets and an asteroid belt .
Our measurement of 0.674 \pm 0.014 milli-arcseconds for the limb-darkened angular diameter of this star leads to a physical radius of R _ { * } = 0.9058 \pm 0.0190 R _ { \odot } and luminosity of L _ { * } = 0.622 \pm 0.014 L _ { \odot } when combined with a fit to the spectral energy distribution of the star .
Placing these observed values on an Hertzsprung-Russel ( HR ) diagram along with stellar evolution isochrones produces an age of 10.6 \pm 4 Gyr and mass of 0.863 \pm 0.043 M _ { \odot } .
We use archival optical echelle spectra of HD 69830 along with an iterative spectral fitting technique to measure the iron abundance ( [ Fe/H ] = - 0.04 \pm 0.03 ) , effective temperature ( 5385 \pm 44 K ) and surface gravity ( \log g = 4.49 \pm 0.06 ) .
We use these new values for the temperature and luminosity to calculate a more precise age of 7.5 \pm 3 Â Gyr .
Applying the values of stellar luminosity and radius to recent models on the optimistic location of the habitable zone produces a range of 0.61-1.44 AU ; partially outside the orbit of the furthest known planet ( d ) around HD 69830 .
Finally , we estimate the snow line at a distance of 1.95 \pm 0.19 AU , which is outside the orbit of all three planets and its asteroid belt .