Precise orbital parameters,masses, and parallax of the subgiant binary system 12 Persei: a combined spectroscopic–interferometric analysis

In this work, we determine the orbital parallax of 12 Persei from a combined spectroscopic and interferometric solution and compare it with those from Gaia and Hipparcos to assess their consistency. We refined previous astrometric measurements and utilised precise orbital parameters and mass ratios derived through MCMC data, adjusted with the Tokovinin dynamical method and least squares. This led to a solution that was statistically consistent with both historical and new observations. By combining the visual and spectroscopic solutions, we accurately fit the system's mass components and orbital parallax, and recent data confirm these estimates. We derived the stars' effective temperatures, radii, and luminosities through synthetic photometry relation techniques, further validating our model when compared with observational data. Physical parameters were obtained from modified orbital elements using the Tokovinin and Al-Wardat methods. We identified 12 Per as part of the subgiant stars group in analysing magnitudes, colour indices, and magnitude differences. Our study indicates that 12 Per consists of stars of spectral subclasses F6.5IV and G1IV in the subgiant phase, likely formed by fragmentation. This work provides an independent validation of the orbital parallax through agreement with Gaia astrometry, makes a significant contribution to understanding subgiant stars, and lays the groundwork for future higher-resolution observations and improved modeling techniques.