RV curve of the metal-rich exoplanet host star XO-7

We report the discovery of the transiting hot Jupiter XO-7b and of a second, massive companion on a wide orbit around a circumpolar, bright, and metal-rich G0 dwarf (V=10.52, T_eff_=6250{+/-}100K, [Fe/H]=0.432{+/-}0.057dex). We conducted photometric and radial velocity follow-up with a team of amateur and professional astronomers.

XO-7b has a period of 2.8641424{+/-}0.0000043days, a mass of 0.709{+/-}0.034M_J_, a radius of 1.373{+/-}0.026R_J_, a density of 0.340{+/-}0.027g/cm^3^, and an equilibrium temperature of 1743{+/-}23K. Its large atmospheric scale height and the brightness of the host star make it well suited to atmospheric characterization. The wide-orbit companion is detected as a linear trend in radial velocities with an amplitude of ~100m/s over two years, yielding a minimum mass of 4M_J_; it could be a planet, a brown dwarf, or a low-mass star.