Physical Properties of the Binary Star 12 Persei

We have obtained new radial velocities of the double-lined spectroscopic binary star 12 Persei, whose period is 331 d, and which has been resolved in recent years by speckle interferometry. We derive a solution for the orbital elements from the speckle and radial velocity data simultaneously, and find from that solution masses of 1.306 +/- 0.035 solar masses and 1.172 +/- 0.030 M for the components, and an orbital parallax of 0.04224 +/- 0.00056 arcsec. We also determine spectroscopically the difference in magnitude between the components and, hence, their absolute magnitudes. We estimate their spectral types and individual colors by fitting standard-star colors to those observed and use those results to find effective temperatures, bolometric corrections, and radii, and hence surface gravities and mean densities for the components. We find projected rotational velocities. The stars seem to be well above the zero-age main sequence, but appear to have metallicities greater than the sun; if so, they would lie closer to one appropriate to their metal content. (Author)