Caracterización del sistema HD 196385 mediante imagen directa, velocidad radial y astrometría

Abstract

In this paper we present a characterization of the relative orbit of HD 196385B combining data from direct imaging, radial velocity, and proper motions from the Hipparcos and Gaia missions. To perform a joint fit of the data, we used the code orvara. From the fit, we obtained ranges of possible values for the major semi-axis, the mass of the secondary component, period, eccentricity, inclination, the argument of the periastron and longitude of the ascending node. Both the semi-axis (37_-8⁺¹¹ AU) and the mass of the companion (0.24_-0.06^+0.10 M_⊙) showed a good agreement with previous estimates using only radial velocity and direct imaging data. On the other hand, the inclination of the orbit, the argument of periastron and longitude of the ascending node were poorly constrained by this fit. This could be due to the few currently available data. Given the relatively long period of ∼166 years, direct imaging appears as a viable technique to place stronger constraints on the orbital parameters.