SOPHIE and TESS characterization of fourteen TESS Objects of Interest: nine planetary systems and five low-mass stellar companions

Using TESS photometry, SOPHIE radial velocities, ground-based photometry, and high-resolution imaging, the SOPHIE-TESS follow-up program established the nature of fourteen TESS Objects of Interest. Nine systems (TOI-6457, TOI-6883A, TOI-6649, TOI-6842A, TOI-5217A, TOI-6893A, TOI-7025, TOI-7176, and TOI-5893) host planets, while the remaining five (TOI-5621AB, TOI-5321AB, TOI-3678AB, TOI-5906AB, and TOI-5308AB) show large radial-velocity amplitudes indicating eclipsing binaries with companions of 0.1–0.6 M_sun and 0.1–0.6 R_sun.

Among the planet hosts, TOI-6649 b, TOI-6842A b, and TOI-5217A b are transiting hot Jupiters with periods of 4.4–6.0 d, radii of 1.3–1.6 R_J, masses of 0.3–1.3 M_J, and densities of 0.1–0.6 g/cm3. TOI-5217A also has an outer companion, TOI-5217A c, with a period of about 1761 d, a minimum mass of about 13 M_J, and an eccentric orbit (e = 0.53 ± 0.02). TOI-5893 b, TOI-6893A b, TOI-6457 b, TOI-7176 b, and TOI-7025 b are transiting warm Jupiters with periods of 40.4–67.0 d, radii of 0.8–1.2 R_J, and masses of 0.5–1.0 M_J; TOI-6883A b, a recently reported warm Jupiter, is further characterized with new photometry and SOPHIE and TRES RVs, bringing the warm-Jupiter sample to six.

TOI-6842A b is a super-puff with density 0.08 ± 0.01 g/cm3, making it one of the nine lowest-density planets known; its transmission spectroscopy metric of about 250 makes it an excellent target for atmospheric characterization. The six warm Jupiters have equilibrium temperatures of 377–846 K and serve as low-irradiation benchmarks for hot-Jupiter inflation models. TOI-7025 b has an eccentricity of 0.82 ± 0.02, one of the largest known for a planet orbiting a single star.

Finally, using Gaia astrometric excess noise, the team detected TOI-5906 B — the first object identified by the combination of transit, radial velocity, and astrometry.