MILO. I. HD 7449 radial velocities

We unambiguously detect the source of the long-term trend from 0.6-2.15{mu}m at a separation of ~0.54". We use the object's colors and spectral energy distribution to show that it is most likely an M4-M5 dwarf (mass ~0.1-0.2M_{sun}_) at the same distance as the primary and is therefore likely bound.

We also present new RVs measured with the Magellan/MIKE and Planet Finder Spectrograph (PFS) spectrometers and compile these with archival data from CORALIE and HARPS. We use a new Markov chain Monte Carlo procedure to constrain both the mass (>0.17M_{sun}_ at 99% confidence) and semimajor axis (~18 AU) of the M dwarf companion (HD 7449B). We also refine the parameters of the known massive planet (HD 7449Ab), finding that its minimum mass is 1.09_-0.19_^+0.52^M_J_, its semimajor axis is 2.33_-0.02_^+0.01^AU, and its eccentricity is 0.8_-0.06_^+0.08^.