TOI-858 B b: A hot Jupiter on a polar orbit in a loose binary

Abstract

We report the discovery of a hot Jupiter on a 3.28-day orbit around a 1.08 M${}_{Sun}$ G0 star that is the secondary component in a loose binary system. Based on follow-up radial velocity observations of TOI-858 B with CORALIE on the Swiss 1.2 m telescope and CHIRON on the 1.5 m telescope at the Cerro Tololo Inter-American Observatory (CTIO), we measured the planet mass to be $1.10\pm 0.08$ M${}_J$ . Two transits were further observed with CORALIE to determine the alignment of TOI-858 B b with respect to its host star. Analysis of the Rossiter-McLaughlin signal from the planet shows that the sky-projected obliquity is $\lambda =99.3\pm 3.8$. Numerical simulations show that the neighbour star TOI-858 A is too distant to have trapped the planet in a Kozai-Lidov resonance, suggesting a different dynamical evolution or a primordial origin to explain this misalignment. The 1.15 Msun primary F9 star of the system (TYC 8501-01597-1, at $\rho$ ~11") was also observed with CORALIE in order to provide upper limits for the presence of a planetary companion orbiting that star.

Accepted for publication in A&A

References in corpus (25)

• Array Programming with NumPy
• The Gaia mission
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• The Transiting Exoplanet Survey Satellite
• Dynamical Outcomes of Planet-Planet Scattering
• EXOFAST: A fast exoplanetary fitting suite in IDL
• Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes
• A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties
• A stellar-mass-dependent drop in planet occurrence rates
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• A fast hybrid algorithm for exoplanetary transit searches
• Suppression of extreme orbital evolution in triple systems with short range forces
• Orbital misalignment of the Neptune-mass exoplanet GJ 436b with the spin of its cool star
• Friends of Hot Jupiters. IV. Stellar companions beyond 50 AU might facilitate giant planet formation, but most are unlikely to cause Kozai-Lidov migration
• On the Inference of a Star's Inclination Angle from its Rotation Velocity and Projected Rotation Velocity
• A Preponderance of Perpendicular Planets
• Understanding the Impacts of Stellar Companions on Planet Formation and Evolution: A Survey of Stellar and Planetary Companions within 25 pc
• The Rossiter-McLaughlin effect Revolutions: An ultra-short period planet and a warm mini-Neptune on perpendicular orbits
• Detecting the spin-orbit misalignment of the super-Earth 55 Cnc e
• Rotation and Lithium Confirmation of a 500 Parsec Halo for the Open Cluster NGC 2516
• Refined architecture of the WASP-8 system: a cautionary tale for traditional Rossiter-McLaughlin analysis
• Hot Jupiters driven by high-eccentricity migration in globular clusters
• Chromospheric Activity of HAT-P-11: an Unusually Active Planet-Hosting K Star
• The impact of atmospheric dispersion in the performance of high-resolution spectrographs
• Boyajian's Star B: The co-moving stellar companion to KIC 8462852